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Physics/Questions Answered by Expert Steve Johnson

SubjectDate Asked
expansion of liquids2/6/2012
  Q: would it be possible to make mercury thermometre for measuring temperature if expansion of glass is ...
  A: Yes, it would be possible. The scale would be backwards from what we now have on a glass mercury ...
Stationary waves2/4/2012
  Q: One of the characteristic of a Stationary wave is that there is no net energy transfer. ...
  A: When you first studied freefall -- behavior of a dropped object, your analysis ignored the affect of ...
Electrostatics, Gauss' Law2/2/2012
  Q: What is the electrical field inside a nonconducting charged hollow sphere? My Explanation: In both ...
  A: The question implies that the charge distribution is non-uniform, but doesn't give any details. It ...
physics1/31/2012
  Q: A 47 kg heavy object falls 40cm (on this planet) Report states the resulting g"force" is 1.842 I ...
  A: An acceleration on impact of 1.842 g could be legitimate. It depends on additional details. That ...
Mass energy1/29/2012
  Q: Where does the idea come from that energy is "within" mass, when Einstein's equation plainly ...
  A: If we are still talking about the energy of Einstein's equation, then no, it is not the motion of ...
Mass energy1/28/2012
  Q: Where does the idea come from that energy is "within" mass, when Einstein's equation plainly ...
  A: I'm afraid you have misunderstood Einstein's equation. Yes it says that energy = Mass x Velocity x ...
Gravitational potential1/24/2012
  Q: sir In all books and internet the gravitational potential is defined as the negative work done by ...
  A: 1) You need to understand that some mathematical concepts may not make 100% sense logically to most ...
physics1/18/2012
  Q: sir when cycle moves the fricton exerted by ground on front wheel is in backward and in back wheel ...
  A: The front wheel rotates on bearings. Those bearings have friction that would make the wheel stop ...
physics1/17/2012
  Q: does a moving object has impulse?
  A: An object that is moving at constant velocity does not have a impulse. But later if it hits ...
sound waves1/15/2012
  Q: two pipies p1 and p2 are closed and open respectively .p1 has the length of 0.3m.find the length of ...
  A: The formula for p1 (a closed pipe) is Fn = n*v/(4*l) for n = 1,3,5, ... where n is the number of 1/2 ...
Physics help on momentum1/14/2012
  Q: my name is Garett. I am new member here.So I would to ask you help on this question.I'm confident ...
  A: Angular momentum is conserved. Consider the helicopter about to lift off. The main rotor (or blade ...
physic1/11/2012
  Q: sir why all bodies fall to the ground with same acceleration?
  A: I imagine that it seems that a heavier object should fall with higher acceleration. It has a greater ...
gravitational potential energy1/9/2012
  Q: sir can u explain why gravitational potential energy of a two body system is always negative and its ...
  A: Let me start by commenting on a couple parts of your question. You said that the gravitational ...
Physics/Electricity1/7/2012
  Q: Steve, I'm working on project on a science fair project and my topic was electricity. my question is ...
  A: Physics includes the study of electricity. It also includes the study of motion, energy, sound, ...
physic1/3/2012
  Q: sir when is bicycle is in motion,the force exerted by ground on the two wheels acts in what ...
  A: The easy part of the answer is to say the ground provides upward force at both wheels. The sum of ...
Ampere's circuital law...1/1/2012
  Q: Why is ampere's circuital law proves wrong in the case of finite Straight current carrying wire... ...
  A: In the case of an infinitely long wire, B = (mu_0/2*pi)*i/r [Some books write it B = k*i/r] If the ...
electric current12/31/2011
  Q: I'm reading a first year college text which states that while current usually consists of electron ...
  A: Flow of "holes" is often considered with semiconductors. (Holes could be considered in conductors, ...
Science fair- fireproof balloon12/30/2011
  Q: I have a rather simple question about my science fair project . I'm am testing wether or not I can ...
  A: I mostly have questions. Is this balloon the type that can lift a load like a hot air balloon, or a ...
FTL Travel by bending space12/29/2011
  Q: If man were able to create a bubble around a space craft that was capable of bending space by 1 inch ...
  A: I have a slight problem with how you worded that. To be certain what I'm agreeing to, let me say it ...
FTL Travel by bending space12/28/2011
  Q: If man were able to create a bubble around a space craft that was capable of bending space by 1 inch ...
  A: You start with a speed of 1.4667 ft per sec. Then in order to increase the speed to .0833 feet / (1 ...
spray foam and the space act agreement12/24/2011
  Q: I recently discovered the NASA signed a space act agreement that all future space crafts including ...
  A: The NASA agreement is to work with DuPont to jointly develop urethane foam insulation reinforced ...
How to calculate the energy12/21/2011
  Q: A boy rides a bicycle up a hill which is inclined at 30 degree from the ground level. The boy stops ...
  A: All the energy the boy and bike possess when he stops peddling will be delivered to the alternator. ...
physics12/18/2011
  Q: why does not the moon fall towards earth
  A: Well, it does. As we look up at the moon, it has a velocity vector that is perpendicular to our line ...
Momentum12/10/2011
  Q: I am Mr Washington. This is the way I understand inelastic collisions. Please correct me if I'm ...
  A: For the sake of a way to illustrate my explanation, let's talk about a collision of 2 cars of equal ...
physics12/9/2011
  Q: sir why the current should not passed through a potentiometer wire for a long time?and sir can beats ...
  A: Like any resistor, the specifications for potentiometers would limit the power dissipated. It might ...
physics12/8/2011
  Q: Joe holds a stick 2 meters long as he moves past Larry at 0.8c westward. if the meter stick has a ...
  A: I refer you to http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/tdil.html ...
Grade 11 Physics (Motion in Two Dimensions)12/6/2011
  Q: Projectile Motion Calculations A bullet is shot horizontally from a gun. If the bullet's speed ...
  A: One thing needs to be added to the conditions: I will assume the land is flat and level in the ...
physics12/5/2011
  Q: can you suggest an project idea for me in physics-light reflection and refraction includes optical ...
  A: I have found several web sites that might help. Some may be too elementary, some too advanced. ...
velocity calculation12/1/2011
  Q: Sir I am a bit confused in this question and would be very much thankful to you if you answer this ...
  A: Since the road is level, the force of friction will be Ff = mu*N = mu*m*g = 0.80*m*g Newton's 2nd ...
physics11/30/2011
  Q: sir how and why the value g increases if the earth suddenly get stopped rotatting?sir please explain ...
  A: As the Earth rotates, for the direction of my velocity vector to change so I go in a circle with the ...
I need help with the "sources of error" part of this pendulum lab11/29/2011
  Q: We performed a lab involving a pendulum in which we were to find the relationship between the period ...
  A: During the derivation of the formula for period, an assumption is made. ...
Complex 4 Wheeler Automobile Design Model11/27/2011
  Q: This is regarding a Complex 4 Wheeler Automobile Design Model VIZ Cars, Jeeps, Lorries, Bus, Tempo ...
  A: The only benefit to the consumer I see is that if the driver didn't want to back out of a spot where ...
joules, electricity, and animals11/26/2011
  Q: I have an adorable dog and cat that I love to spoil! This includes buying 2 of the following items: ...
  A: I have found no information that suggests using a surge suppressor to protect animals or people. ...
physic11/24/2011
  Q: sir what is the time period of simple pendulum having infinite lenth and how? ANSWER: Hi owais, ...
  A: Ahh yes, you are right. I was too quick to accept the first potential solution I saw. The solution T ...
physic11/22/2011
  Q: sir what is the time period of simple pendulum having infinite lenth and how?
  A: The period of a simple pendulum is given by T = 2*pi*sqrt(l/g) The problem with an infinitely long ...
Boomerang - Laws of Physics11/21/2011
  Q: http://en.wikipedia.org/wiki/Boomerang How does a Boomerang and Returning Boomerang works ? What ...
  A: The shape of the Boomerang and the angular velocity gives the Boomerang aerodynamic lift. The lift ...
physics11/16/2011
  Q: sir in which factor does the light emitted by lan LED depends upon?
  A: This is a topic in the field of solid state physics. Light is emitted when an electron falls into a ...
*gulp* im having a hard time figuring this out11/15/2011
  Q: I just cant get this A worker attaches a safety line to himself but there is nothing to tie him to ...
  A: I'll assume the worker also has 0.30 coefficient of static friction. And I'll assume the 30 degree ...
physics11/14/2011
  Q: sir how can we identify which plate of capacitor is positively charged?
  A: There are several options. Not all options are appropriate in all situations and I don't know your ...
hair raising11/13/2011
  Q: I had a teacher back in school who would scratch her nails on the black board when we got too ...
  A: Interesting to get that question now when there have been stories about recent studies in the news ...
Angular Momentum11/12/2011
  Q: A particle of mass M = 0.89 kg is dropped from a point that is at height h = 2.00 m above the ground ...
  A: If you can get r from Pythagoras, you must know how high point O is above the ground -- I don't. You ...
physics11/11/2011
  Q: Respeted SIR MY QUESTION IS THAT IF TWO MASSE OF 40KG AND 50KG ARE ATTACHED BY STRING AND IF FORCE ...
  A: I will assume the 2 masses are on a horizontal frictionless surface. And that the force on m1 is in ...
Bernoulli's equation11/10/2011
  Q: 1)sir i was going through the derivation of bernoulli's equation . in all sites on internet or any ...
  A: 1) Open both of these websites. ...
physic11/9/2011
  Q: sir i have a question that,if two masses m1 and m2 are moving in same direction and with same and ...
  A: I'm not clear on the situation. I'll add details that I will assume and then answer your question. ...
angular displacement11/7/2011
  Q: can you tell me why finite angular displacement not taken as a vector but infinitesimally small ...
  A: Let's refer to an angular displacement as theta. If angular displacements are to be considered ...
physics11/5/2011
  Q: sir,why the work done is zero when body is moving in a circle?
  A: The formula for work is Work = force*displacement*cos(the angle between force and displacement) ...
Combined Pull11/1/2011
  Q: Why doesn't the moon crash into the earth when the earth is between the moon and the sun ? Two ...
  A: Newton's 1st Law says that objects in motion tend to stay in motion, in a straight line, unless ...
atomic physics10/31/2011
  Q: Why do most stable nuclei have equal number of protons and neutrons?
  A: This isn't my area of confidence, so I searched the web and found some discussions on this. ...
physics10/30/2011
  Q: 1. Ramesh buys six bottles of syrup each containing 1 litre. Each empty bottle weighs 400g. The ...
  A: First let me show you the normal way to show exponents here. 1.2 g/cm^3 where ^ is shift+6 (on my ...
Physics10/27/2011
  Q: You’re an accident investigator at a scene where a drunk driver in a 1600kg car has plowed into a ...
  A: The frictional force of the combined wreckage is given by Ff = mu*N = mu*m*g = 0.74*(1600 kg + 1400 ...
gravity force10/23/2011
  Q: is everything wrong in my statements? i explain myself the gravity on the earth as a force counter ...
  A: I'm afraid I don't understand all that you have said. But as a rule, I can't see gravity and ...
A 5kg object on a string is whirled with constant speed in horizontal circle?10/21/2011
  Q: A 5kg object on a string is whirled with constant speed in horizontal circle? A 5kg object on a ...
  A: 1) The data you wrote up disagrees with what's in the figure that your link brought up. I'll go with ...
falling bodies10/19/2011
  Q: I dont know how to solve these problems... A pop-fly ball is hit. The fans time the ball's flight ...
  A: You were probably given a set of kinematic formulas. Vf = Vi + a*t d = (Vi + Vf)*t/2 d = Vi*t + ...
velocity10/17/2011
  Q: I was hoping if you could help me out with this problem: A toy car goes 10.3 meters in 4.15 seconds ...
  A: Constant velocity: if your car's speedometer reads exactly 50 km/hr during a 5 second time period, ...
2-dimensional motion10/14/2011
  Q: A soccer player is standing on the edge of a cliff that stands 40.0 meters above a pond. The soccer ...
  A: There may be some missing information here about the original direction of the kick. I'll assume the ...
mAh and batteries10/11/2011
  Q: I have a portable house phone that has a 2.7mAh 3.6V rechargeable battery pack. Am I safe to replace ...
  A: I'm reluctant to recommend that. Rechargeable batteries come in many different technologies. You ...
alternating current10/10/2011
  Q: A lamp of 100W,120V is to be operated from 230V,50Hz a.c . Which of the following method should be ...
  A: The lamp needs to have the normal current going through it to give off the normal light. A resistor ...
centre of mass10/8/2011
  Q: Sir I just want to know how to find centre of mass of any rigid body.plzzz give an algorithm or step ...
  A: Check out these websites to find it by experiment. ...
prashant_akerkar@yahoo.com10/7/2011
  Q: http://en.wikipedia.org/wiki/Echo_%28phenomenon%29 1. why echo only in specific places/areas ? - ...
  A: 1. In this answer I am thinking about an echo audible to the human ears. See my answer to #2 for ...
equilibrium10/5/2011
  Q: Why do high heels worn by a lady walking on a wooden floor leave impressions on the floor? Why do ...
  A: high heels: The answer to this is pressure. It's not so much related to equilibrium. Consider a man ...
Electric potential10/4/2011
  Q: Give examples of situations in which the potential of a charge body has a sign opposite to that of ...
  A: potential: Potential is short for potential difference. Usually the phrase "potential of a body" is ...
electrical engg.10/1/2011
  Q: can you please tell me that how speed varies linearly with torque in a dc motor.But when we draw the ...
  A: I agree when you say that "when we draw the characteristics of dc motor, ... speed varies inversely ...
Elem. College Physics (101)9/27/2011
  Q: A stone has a mass of 5.71 g and is wedged into the tread of an automobile tire, as the drawing ...
  A: We will need the stone's mass in kg, so let's do that conversion first. m = 5.71 g * (1 kg/1000 g) = ...
Chemistry9/24/2011
  Q: How much work is done when a 135g tomato is lifted 11.4m ? I want to know how to work this problem. ...
  A: To simplify things in the early days of learning Physics, we assume the tomato is lifted at constant ...
mechanics9/23/2011
  Q: Sir, it is easy for us to balance a bicycle when we are going fast , but it becomes more difficult ...
  A: For a webpage with a good discussion of bicycle dynamics, go to ...
electrostatic9/21/2011
  Q: please tell me why it is that to limit coronal discharge on this dirod electrostatic generators ...
  A: I'm sorry but I don't know much about electrostatic generators. So this is a guess. Perhaps the U ...
Conservation of linear momentum9/20/2011
  Q: Sir i am not able to understand how to solve the following question A gun is mounted on a railroad ...
  A: I agree with your result for after the 1st shot. But that velocity is with respect to the ground. ...
Solve please9/19/2011
  Q: 1)A ship is sinking in the dark ,the sailors on the ship fire a distress flare into air.it explodes ...
  A: Velocity = the distance traveled / the time interval You were given the velocity. So is the time ...
Scalars and Vectors - Examples9/18/2011
  Q: http://en.wikipedia.org/wiki/Scalar_%28physics%29 Scalars are physical quantities which have ...
  A: Not all the items in your list pass the test to be called a physical quantity. Note that in the site ...
Gauss' law9/15/2011
  Q: Suppose that a Gaussian surface enclose no net charge. Does Gauss' law require that electric field ...
  A: Does Gauss' law require that electric field equal to zero for all points on the surface? No. It ...
TEMPERATURE - PRESSURE RELATIONSHIP.9/11/2011
  Q: May I just ask about the discovery of the Temperature - Pressure Relationship Law, also famous as ...
  A: Check these links: http://en.wikipedia.org/wiki/Gay-Lussac%27s_Law ...
Rechargeable batteries9/9/2011
  Q: I have few doubts about Rechargeable batteries. 1*How many hours(max) can they be left for ...
  A: Different battery technologies have different charging requirements. Refer to the owner's manual ...
physics9/8/2011
  Q: i only have 5 days to do my investigatory project. what i want is to have an invention. any field of ...
  A: There are so many different topics I could suggest. But it should be a topic that interests YOU. And ...
Electric field9/7/2011
  Q: Sir, I would like ask three questions. 1. A point charge is moving in an electric field at ...
  A: 1. Yes, the path the charge follows is analogous to the path of a projectile fired horizontally. The ...
Potential and Kinetic Energy9/6/2011
  Q: What is the formulea for Kinetic and Potential energy?
  A: The formulae for Kinetic and Gravitational Potential energy are: KE = (1/2)*m*v^2 and GPE = m*g*h ...
friction9/3/2011
  Q: Sir i want to know that why rolling friction is less than the sliding friction? Also what is meant ...
  A: Sliding friction is also called kinetic friction. In either case, it is due to 2 surfaces sliding ...
physics8/25/2011
  Q: a 16g mass moving in the +x direction at 30cm/s while a 4g mass moving in the -x direction at ...
  A: You should use the principle of conservation of momentum for this problem. The description doesn't ...
physics8/24/2011
  Q: hi I am looking for some explanation on how physics explain how battery works
  A: These 2 webpages will probably give you more than you need. ...
van allen belts8/23/2011
  Q: When scientist say that the Van Allen belts are radioactive what do they mean.Is it like that they ...
  A: There may be a small amount of uranium up there, but it's mostly electrons and protons. See ...
formula8/22/2011
  Q: there is a formula mid way through this page ...
  A: The formula f = 1/(2*Π*√(L*C)) is equivalent to T = 2*Π*√(L*C) because f = ...
conservation of linear momentum8/20/2011
  Q: sir i have questions in conservation of linear momentum. During explaining conservation on linear ...
  A: (Sorry I took a long time for this one.) 1) When you start to consider a system, you are going to ...
Shadow Matter and its implications8/18/2011
  Q: My name is Alexander,45,living in Toronto,Canada.I am Software Quality Assurance Analyst,but like to ...
  A: Shadow matter sounds like a wild hypothesis to me. Humans having 2 bodies and 2 brains? Well, my ...
Water bending with comb and varying temperatures of water8/17/2011
  Q: Does changing the water temperature from cold to luke warm to hot vary the amount you can bend water ...
  A: You mentioned a comb in the Subject name but the comb is not mentioned in the question. I'll try to ...
Capacitor EMP8/15/2011
  Q: hope you do not mind me continuing the Q & A.? so how could i find out the peak rise times of the ...
  A: I haven't been able to find enough details of the circuit. I saw forums where people asked about ...
circular motion8/11/2011
  Q: sir in vertical circular motion of a bob tied to a string and being rotated from the other of the ...
  A: For the bob to follow a circular path, it requires centripetal force directed to the center. The ...
EMF8/10/2011
  Q: I live about 300 feet away from hi power lines. I recently bought a gauss meter (dr.gauss name) to ...
  A: During college, EMF stood for electro-motive-force. But I found an explanation of how EMF is used by ...
Multi meter8/6/2011
  Q: Sir, could i check the amps hour capacity of a particular battery by using multi meter?
  A: In general, no I don't think so. Consider a battery that has had 1/2 of its fully charged amp-hours ...
Scientific Notation8/5/2011
  Q: A brochure for the 1963 Ford Falcon said it averaged 26 miles per gallon of petrol. A 2002 Falcon is ...
  A: First let me correct you on terminology. This question is not about Scientific Notation. Scientific ...
Human Being Resistance Power.8/3/2011
  Q: Human Being Body is a Good Conductor of Electricity (consists of watery fluids) since Water is good ...
  A: I agree with the replies you got from the forum: "Every human has the same LOW resistance on the ...
aluminium8/2/2011
  Q: Aluminium is a good conductor of electricity but is non magnetic ..I thought since electricity and ...
  A: Wikipedia says in http://en.wikipedia.org/wiki/Magnetism that "In magnetic materials, sources of ...
spherical surface7/31/2011
  Q: Find the electric field everywhere if a spherical shell of inner radius R1 and outer radius R2 has a ...
  A: I believe these web sites will guide you to your answer: ...
Human Being Resistance Power.7/30/2011
  Q: Human Being Body is a Good Conductor of Electricity (consists of watery fluids) since Water is good ...
  A: A wide variety of measurements can be obtained, depending on method. If the skin is dry, the ...
centripetal force7/29/2011
  Q: sir the centripetal force is required to maintain a circular motion. Now in all books it is said ...
  A: It's typically said that centripetal means toward the center (from Greek or Latin or something). In ...
regarding mass calculation7/28/2011
  Q: If a rod of 2 meter is loaded with a weight of 10 kg at one end and a brick is placed as point ...
  A: This is a matter of the torques summing to zero. Need to chose a point of rotation. It could be any ...
Mirrored Numbers - (Exact Replica of the Number) - Optics & Real Life Use ?7/26/2011
  Q: What i observe by looking at the Numeric Whole Numbers(Integers) in Mirror (Glass) Object are the ...
  A: Regarding this series being useful in physics, perhaps optics, I think not. But perhaps that's a ...
Physics-Gravity7/25/2011
  Q: A sphere of solid of specific gravity 8, has a concentric spherical cavity and just sinks in water. ...
  A: Assignment questions are OK with me. In my answer, I always try to guide rather than give the ...
pendulum7/24/2011
  Q: A pendulum is hung at rest with an angle of 40 degree from the negative x-axis. Then the pendulum is ...
  A: Make a drawing and be certain that you agree with what I'm saying in this paragraph. The pendulum ...
Physics7/23/2011
  Q: How does mass affect the acceleration of an object sliding down on a frictionless inclined plane? Is ...
  A: 1. The force accelerating the object down the slope is the component of its weight that points down ...
Physics: Dynamics7/22/2011
  Q: this is myBlock A weighs 2.70N and B weighs 5.40N. The coefficient of friction between all surfaces ...
  A: Edit: In my original answer, I neglected to carry the minus sign through in the line that finds the ...
Physics7/21/2011
  Q: a body is dropped from the tower an reaches the ground in 3sec. calculate the height of the tower?
  A: Use the kinematic formula y = Vi*t + (1/2)*a*t^2 where y is the height of the tower, Vi = 0, a = g = ...
magnetism..7/20/2011
  Q: Sir , It is told that if two wires , carryin same current , in same direction are placed parallel ...
  A: The 2 wires attract each other because each current is in the magnetic field generated by the other ...
Physics - Capacitance7/19/2011
  Q: 1. Describe the capacitance of parallel plate capacitors in regard to: a) The area of the plates b) ...
  A: I've found writeups that I hope will answer your questions more clearly than I can. 1. The equation ...
physic7/18/2011
  Q: This is a free fall question. Vo=44 m/s t=14.1s h2=? i already know the answer but i need to know ...
  A: The kinematic formula for the very general case is d = do + Vo*t + (1/2)*a*t^2 where d is the ...
Inductor charging 12/3/20067/17/2011
  Q: You have this formula in your response to an Inductor charging question on 12/3/06: E = (I^2)R + ...
  A: You are right that I^2*R is power. I think you misread my answer to that question. I wrote "The ...
Help Me Please =]7/15/2011
  Q: A motorcyclist who is moving along an x axis directed toward the east has an acceleration given by a ...
  A: Let me show you the normal way to show exponents here (and similar sites). (6.1 - 1.5t) m/s^2 where ...
Ideas for working model in physics7/14/2011
  Q: Sir, I want to know how to make a working model in physics on topic 'laws of motion'?
  A: Any AllExperts.com web page has a search window. I put [working model laws of motion] in one of ...
impact of earth's revolition on flying aeroplanes7/13/2011
  Q: WILL THE DESTINATION COMES NEARER WHEN THE AEROPLANE IS FLYING DUE TO EARTH'S REVOLUTION ...
  A: LAXMAN, If you board a train at one end, and decide to walk to the other end after the train gets ...
Physics7/12/2011
  Q: The shaft connecting a turbine and an electric generator in a power plant is a solid cylinder of ...
  A: This website has a list of moments of inertia (also called rotational inertia) ...
Fluid7/10/2011
  Q: You are working as a summer intern for the Illinois Department of Natural Resources (DNR) and are ...
  A: a) I will guess that the lake is on the right side. So the left side of the plug has atmospheric ...
pendulum7/9/2011
  Q: when a person falls from a building with a pendulum in his hand, the time period of the pendulum is ...
  A: During the fall, the pendulum would behave as if it was in zero gravity. The period of a simple ...
friction7/8/2011
  Q: sir there are many doubts in friction. I hope you wont mind for me asking so many questions at a ...
  A: I have revised my answer adding my thoughts on 4 and 7. You will find that I disagree with the ...
work7/7/2011
  Q: sir i m studying about conservative forces. In my textbook it is defined that work done by ...
  A: Let me review how the formula 1/2 kx^2 was developed. The basic work formula is W = F*d If the ...
work7/6/2011
  Q: sir i m studying about conservative forces. In my textbook it is defined that work done by ...
  A: The problem is where you calculate the work done by the spring when it's allowed to retract from 5 ...
On which principle is the Electrostatic Radiant Impulse concept of Nikola Tesla based ?7/5/2011
  Q: I would like to ask you an original question. It is always said that Nikola Tesla used the ...
  A: Good to hear from you. I'm well, hope you are still enjoying your quest. About the question in ...
RF basics7/4/2011
  Q: asking a basic question. is the AC of the RF output to antenna in modern FR transmitter. A) a ...
  A: Sorry but I don't understand what you mean by ++++++. I assume you are talking about how you will ...
friction7/2/2011
  Q: Sorry I didnt upload the diagram for the following question . NOw I have sent the diagram . pLease ...
  A: I again did not get the diagram. Perhaps the feature is temporarily down. Or perhaps you didn't know ...
The Cookie Question7/1/2011
  Q: Hey Steve, John Boone here, the 90s expert over in Music. I have a hypothetical question that ...
  A: The cookie would have gyroscopic properties. Let's use the axis names roll, pitch and yaw used in ...
Projectiles/Momentum6/28/2011
  Q: A projectile is fired at an angle of 60 degrees with a velocity of 400m/s. At the highest trajectory ...
  A: By basic projectile analysis you can find the time to the highest point in the trajectory. That ...
relativity6/27/2011
  Q: sir, is it possible to impart a hollow sphere the speed of light, such that it continues to rotate ...
  A: Let me take that a step at a time. "is it possible to impart a hollow sphere the speed of light" No, ...
physics6/26/2011
  Q: two cars A and B start from the same point at the same time and travel along straight roads that ...
  A: Make a triangle from the 2 paths the cars follow and a line drawn between the locations of the 2 ...
Color Theory6/25/2011
  Q: I was wondering why all primary color systems (RGB, RYB, CYMK) all have 3 colors? I mean sure the ...
  A: I am nowhere near expert in color systems. I did find some things via searches. The site ...
physics6/24/2011
  Q: Let the resistance of an electric component remains constant while the potential difference across ...
  A: First the logical approach: The value of the potential difference across the ends of the component ...
RF basics6/23/2011
  Q: asking a basic question. is the AC of the RF output to antenna in modern FR transmitter. A) a ...
  A: I need to ask you for a followup with more details. I don't understand the term FR transmitter. It ...
internal combustion engine6/22/2011
  Q: what is burnt in internal combustion engine of a car to release energy for the car to move? can it ...
  A: Gasoline, diesel fuel, and propane are some fuels that are burned in internal combustion engines of ...
mountain biking descent speed6/21/2011
  Q: I am doing a school project on physics in mountain biking. I am trying to find some equations which ...
  A: This is going to be a guess. If you're correct that it's faster to roll over the obstructin than ...
phys6/19/2011
  Q: A 1300kg car runs into the rear of a 1700-kg minivan that was moving at 5m/s. The two vehicles are ...
  A: a) Momentum would be conserved. The relationship is m1*u1 + m2*u2 = (m1+m2)*v where the u terms are ...
electricity6/18/2011
  Q: I am an electrical engineer and we liken electron flow in a wire to water flowing in a pipe... is it ...
  A: If you're thinking in terms of conventional current with positive charge carriers, then yes, the ...
Projectiles of and under hand serve and an over hand serve6/17/2011
  Q: What serve will be more likely to use if you are wanting to have a more effective and accurate ...
  A: I'm not sure with which motion you could apply more force to the ball. It probably has to do with ...
physics6/16/2011
  Q: an airbus A320 jetliner has a take off mass of 75000kg. it reaches its takeoff speed of 82m/s ...
  A: Find the acceleration using the kinematic formula Vf = Vi + a*t where Vf = 82 m/s, Vi = 0, and t = ...
error analysis6/15/2011
  Q: Sir I am doing the chapter error analysis in measurement. In that 1) one statement in given that the ...
  A: The rule you were given talks about the least count of the instrument. From that I assume that the ...
Electrostatics6/14/2011
  Q: Respected Sir, I have a question and I don't know how to proceed.So here it is. ...
  A: First let's decide how much of what gauge wire we're talking about. I choose 0.1 m of 22 gauge solid ...
phyisics6/12/2011
  Q: want to make a working model of physics on the 3 laws of newton...please help me out someone!!have 7 ...
  A: I have some web sites for you to look at. 1st: ...
relative velocity6/10/2011
  Q: Sir I am doing the man swimming in iver problems. THere is one question 1) A man can swim at a speed ...
  A: When they say the man's velocity with respect to still water is the same as the man's velocity with ...
Cliff and Projectiles6/8/2011
  Q: A ball is thrown from the brink of a cliff 10 m high with an initial velocity of v0 = 4 m/s at an ...
  A: a) 4sin(31)-.5(-9.8)t^2 is a good try, but there are some things left out -- t and y. It should be y ...
Problem on Moment of forces:6/6/2011
  Q: A crane is used to raise one end of a 15KN girder of length 10 m off the ground. When the end of the ...
  A: a) We have equilibrium, therefore the net torque must be zero. The angle between ground and the ...
force of hail balls hitting concrete6/5/2011
  Q: I would like the how much force is seen at the moment of contact when a 6 ounce hail ball coming ...
  A: I need to convert those ounces to kg. 6 ounces*1 kg/35.27 oz = 0.17 kg According to Wikipedia, ...
physics6/4/2011
  Q: what problems we can face while using a galvanometer and how we can get rid out of this problem?
  A: Parallax is one problem. Carefully set your line of sight to be perpendicular to the face of the ...
Physics 16/2/2011
  Q: A physical pendulum is constructed from a uniform thin rod of length L suspended from one end. The ...
  A: I'm looking in my book at the derivation of the equation of motion for a simple pendulum for ...
photons6/1/2011
  Q: .I never knew that all EM Radio waves to Gamma rays are all photons.I have read many physics text ...
  A: Look at this website http://physics.about.com/od/lightoptics/f/photon.htm In the section titled ...
physics-motion5/28/2011
  Q: A car accelerates from rest with a constant acceleration ‘A’ on a straight road. After gaining a ...
  A: Section 1: During the constant acceleration ‘A’, call the time ta and distance Sa. Vave = d/t so t ...
Physics/Art Idea5/27/2011
  Q: I was thinking it might cool if there was a series of thin clear tubes like straws creating a grid ...
  A: I don't really have a feel for art, so I don't know exactly what you want to do. But it appears that ...
electricity : resistance5/24/2011
  Q: Three bulbs of 100 WATTS each are connected in series in an electric circuit . In another circuit ...
  A: a) No, the bulbs in the parallel circuit will be brightest. In both circuits, the electrons that ...
damping time and resonance curve5/20/2011
  Q: I am having trouble with the second part of this problem: The drumhead of a kettledrum has a ...
  A: a) The amplitude of the oscillation would follow an equation of the form x(t) = ...
speed of propagation5/19/2011
  Q: How many times greater or smaller should the musician make the tension (F) on the string to triple ...
  A: We can answer this using dimensional analysis. It seems reasonable to expect that the velocity ...
Physics5/18/2011
  Q: Car A with a mass of 620 kg is traveling at a speed of 42 m/s in the direction of 30 degrees N of E. ...
  A: I don't think your problem is good. Two things: The paths of car A and car B cross. Like they go ...
Working model5/14/2011
  Q: .... I am a class 10 student.I want your advice, as i have to make a working model on any of the ...
  A: It would be best for you to choose something that interests you, and perhaps there is one in your ...
The working Model!5/13/2011
  Q: I am Cheryl, a Tenth grade student. I need to make a WORKING MODAL but am confused about what to ...
  A: It would be best for you to choose something that interests you, and perhaps there is one in your ...
physics5/12/2011
  Q: why and when does electric spark occur?
  A: why does electric spark occur? You know that opposite charges attract. If they can move, they will ...
potential division5/10/2011
  Q: When a battery of V volts is connected to a load resistance through a resistor R,then the potential ...
  A: When there is a potential difference, there is an associated electric field according to Vb-Va = E*d ...
Physics5/8/2011
  Q: An object is placed to the left of a convex lens and on the optical axis. The object is 30 cm from ...
  A: The magnification is given by m = -i/o where i and o are the image and object distance from the ...
Physics5/7/2011
  Q: An electric motor on an airplane operates on 20.1 volts and draws a current of 12.9 amperes. How ...
  A: Well no, you multiply by the 6 hours' worth of seconds. Here's the solution: 6 hrs. = 21600 seconds ...
Physics5/6/2011
  Q: An electric motor on an airplane operates on 20.1 volts and draws a current of 12.9 amperes. How ...
  A: The power consumption is given by P = V*I where V = 20.1 Volts and I = 12.9 amps. The result will be ...
physics5/5/2011
  Q: Find the stress in the bone of the upper arm,humerus when a 30lb weight is lifted in the hand.The ...
  A: I will assume the forearm is held horizontally and the upper arm is vertical. The weight is held ...
Question about the Chernobyl Disaster and Physics5/4/2011
  Q: I was wondering if there was a connection between the Chernobyl Disaster and any part of Physics as ...
  A: Physics is very much connected to the operation of a nuclear reactor -- either safely or during ...
Rainbow's Spectrum5/3/2011
  Q: A Rainbow's light is spread across the visible spectrum from red [low freq.] to violet [high freq.]. ...
  A: There's an interesting discussion at ...
how far does light go?4/30/2011
  Q: I go to high school and I have to research a theory either 1.Light goes forever and only dies out ...
  A: If the light is a beam of light from a laser, and it's pointed out into space and never hits an ...
Physics-Force and Energy4/29/2011
  Q: Hey Steve, how's it going my friend? I am back again after a few months!:D... I have a question here ...
  A: Welcome back Patty, Study the system energy involved. There was the original kinetic energy, there ...
Simple Harmonic Motion4/27/2011
  Q: The wheel of a sport car is suspended below the body of the car by a vertical spring with a spring ...
  A: The differential equation that describes simple harmonic motion is d^2x/dt^2 = -(k/m)*x where in ...
Full, Continuous, Concurrent Rotation on Multiple Axis4/26/2011
  Q: I am currently working on a personal project to develop a machine with the human body as an integral ...
  A: Perhaps I need further clarification, but let me proceed as though my interpretation is accurate. ...
photographic plate4/22/2011
  Q: in most of the properties of elements ,we acquainted with this line "it affects the photographic ...
  A: I'm not familiar with that phrase being in the properties list of most elements. I don't even see ...
question on light4/20/2011
  Q: A flat glass slab of thickness 6 cm and refractive index 1.5 is placed in front of a plane mirror.An ...
  A: The distance between observer and his image would be 1 meter if hte slab had not been there. While ...
Scattering4/19/2011
  Q: Sir had few doubts related to scattering 1) We say that sun light is white in color. But when we ...
  A: I have some reading on the subjects for you. http://en.wikipedia.org/wiki/Rayleigh_scattering ...
Orbital centrifugal force4/18/2011
  Q: Does an earth "passenger" weigh less at midnight when the earth's orbital centrifugal force tends to ...
  A: Yes, but it's a very slight difference. There is a similar question that has been asked about the ...
electricity4/17/2011
  Q: We know that electricity is produced by moving charges but specifically what is is about that motion ...
  A: The charges move because they are attracted by the potential ahead of them and repelled by the ...
electricity4/16/2011
  Q: what is the resultant inductance when two inductance are connected in (a) series and (b) parallel?
  A: I'm going to show you by analogy to resistors. a) Series: You know that resistors in series are ...
lightning and planes4/15/2011
  Q: I was on a plane recently and we had to make a detour to avoid a storm.As we skirted around the ...
  A: These websites discuss the risks lightning pose to airplanes. ...
question on rotational motion4/14/2011
  Q: A thin uniform rod of mass 'M' and length 'L' is hinged at its upper end,and released from rest from ...
  A: So it's as if you suspect a weak point 1/3 of the way down the rod and want to make sure it doesn't ...
projectile4/13/2011
  Q: A football quarterback throws a pass at an angle of 32.8°. He releases the pass 3.50 m behind the ...
  A: The ball will be in the air for a time t and go downfield a distance x. The receiver will run for a ...
Friction Calculation4/11/2011
  Q: Can u Provide me simple formula to calculate friction. I can not solve this formula everytime It may ...
  A: No I can't. Friction is a complex phenomenon. The coefficient of friction has to be measured for ...
question on alternating current4/8/2011
  Q: An ac source v = v'sinwt (v=rms voltage and v'=peak voltage) is connected across resistance 'R' and ...
  A: I have a problem with saying that v=rms voltage. The expression for v is a function of t. When t is ...
Physics4/6/2011
  Q: A flat-bottomed rectangular boat is 4.0 m long and 1.5 m wide.If the load is 2000 kg (including the ...
  A: Let me assign these variable names: mass of boat and load = mb mass of water pushed out of the way = ...
Physics4/5/2011
  Q: When a Fletcher's trolley rolls down an inclined plane, does it undergo uniform accelerated motion?
  A: I don't think I've seen a Fletcher's trolley in person. I searched online and found photos from ...
Newton's second law4/4/2011
  Q: The horizontal surface on which the block of mass 4.3 kg slides is frictionless. The force of 21 N ...
  A: It's good that you showed what you have tried to do. That formula would give you the magnitude of ...
physics4/1/2011
  Q: a book kept in a vertical position has less stability than a book kept in normal position. y?
  A: I assume the position you're calling normal is when it's laying flat. Because laying flat, with the ...
ecology A3/31/2011
  Q: why is time an important factor in the process of evolution by natural selecton?
  A: I'm not a biologist or geneticist. But this is my interpretation. Most often, reproduction produces ...
deriving an equation3/30/2011
  Q: deriving an equation for Q and T power screw covering lead.
  A: I'm sorry, this is outside my experience/knowledge. Perhaps you need the Mechanical Engineering ...
physics3/29/2011
  Q: A needle of a sewing machine is oscillating in simple harmonic motion with a vertical displacement ...
  A: I will assume 0.2 cm is the displacement from the highest position of the oscillation to the lowest ...
Angular and lateral movement3/28/2011
  Q: Suppose there is a body of some shape and mass. It is not affected by gravity or drag. At first it's ...
  A: I assume the force is applied briefly, for a time t. During that time t, the center of mass, COM, ...
Physics (Coefficient of Static Friction)3/26/2011
  Q: Hey Steve, how's it goin? I desperately need to know how to solve these problems, Thanx alot I ...
  A: The hint I referred to was "Then at the limit, the friction, Ff, must equal to Wh." (Sorry that my ...
physics thermodynamics3/25/2011
  Q: Sir, if a hollow sphere of radius R a hollow cube of side R and a Thin plate of radius R made up of ...
  A: I will assume that all surfaces are exposed to the air. That might require hanging all three with ...
Physics3/24/2011
  Q: I am lost on how to go about with formulating an equation for the followingA small object of radius ...
  A: a. The initial energy in each case is the gravitational potential energy, m*g*R. This energy is ...
Moment of Inertia and stability3/23/2011
  Q: Is there any relation between the magnitude of Moment of Inertia(I) and the stability of rotation ...
  A: You can use the same magnitude of torque to stop rotation with I equal to either I' or I". But it ...
Pendulum Physics3/21/2011
  Q: Consider two simple pendulums with identical masses but with different lengths (L1=223.43cm and ...
  A: L1 will be back at A after 3 s, 6 s, 9 s, 12 s, ... L2 will be back at A after 4 s, 8 s, 12 s, ... ...
Physics (Coefficient of Static Friction)3/20/2011
  Q: Hey Steve, how's it goin? I desperately need to know how to solve these problems, Thanx alot I ...
  A: a) Let the total weight be W and the weight of the hanging portion be Wh, so that the portion on ...
Physics3/18/2011
  Q: What is average velocity and what is refractive index?
  A: Average velocity: Suppose you were on a 100 km road trip. Some of the trip was on city streets and ...
Physics3/17/2011
  Q: A viewing window in the aquarium is 62 inches wide and 45 inches high. If the average pressure of ...
  A: Pressure is in units of psi, which is an abbreviation for pounds per square inch. That might give ...
gravity and mass3/16/2011
  Q: Ball A is fired horizontally directly towards a similar ball B. At exactly the same moment B is ...
  A: If ball B had not been dropped, ball A would have missed. When ball A was fired horizontally, it was ...
Physics3/15/2011
  Q: A 20.0 g copper ring has a diameter of 2.54000 cm at its temperature of 0.000 oC. An aluminum sphere ...
  A: I'll use subscripts (sorry, they don't really descend like a proper subscript should) of c for ...
physics3/13/2011
  Q: A temperature controller, designed to work in a steam environment, involves a bimetallic strip ...
  A: In your introductory chapter on rotational kinematics, you probably have the formula theta = L/R. ...
physics3/12/2011
  Q: describe gauss's law in case of dielectrics.
  A: My reply could be a large write-up, depending on how deep I thought you wanted me to go. I did a ...
physics3/11/2011
  Q: A temperature controller, designed to work in a steam environment, involves a bimetallic strip ...
  A: The coefficients of expansion are Brass 18.7*10^-6 m/m K Steel 13.0*10^-6 m/m K So when an 0.1 m ...
Mastering Physics Question3/10/2011
  Q: A tennis ball gun launches tennis balls at 18.2 m/s. It's pointed straight up and launches one ball; ...
  A: time?: Let y1 be the height of ball 1 when they are at the same height. Let y1 be the height of ball ...
Physics3/9/2011
  Q: Where should the birthday candle of height 5 cm be placed in front of a convex lens of focal length ...
  A: Where: Use the "lens maker's equation" 1/o + 1/i = 1/f where i = 25 cm and f = 15 cm. Solve for o -- ...
Physics3/8/2011
  Q: You have a ball on a wire that is twirled in a circular orbit with a radius of 4.2 m, and the ...
  A: You know, of course, that I cannot "See the figure of a ball on a wire in the Rotation and Angular ...
heat3/7/2011
  Q: I just read in a science magazine that all objects absorb infra red radiation? I an next to a ...
  A: The question of whether or not all objects absorb infrared radiation is more complicated than yes or ...
Physics ball falling at terminal velocity3/4/2011
  Q: A 22 (cm) diameter bowling ball has a terminal speed of 77 (meters per second). What is the ball's ...
  A: The formula for terminal velocity is Vt = sqrt(2*m*g/(rho*A*Cd)) where g = 9.8 m/s^2, rho is the ...
Physics3/3/2011
  Q: the microwave oven has a current of 12.3 A when operated using a 120V power source. How much power ...
  A: The basic formula for power is P = V*I Using that formula with V = 120 V and I = 12.3 A yields P = ...
Mechanics - Biking Paradox3/1/2011
  Q: When trying to understand the basic relationships between force, power and energy by applying the ...
  A: The new bike has less friction, so I can increase the speed until the air drag increases so that I ...
Intro to Physics2/28/2011
  Q: The specific gravity of a particular liquid 6.5. What would be the weight (in pounds) of .50ft^3 of ...
  A: A substance with specific gravity of 6.5 has density that is 6.5 times that of water. The density of ...
First year physics question2/27/2011
  Q: This is a first year physics question that I'm really stumped by. Here it is: A small ball with ...
  A: The formula that gives the period T in Simple Harmonic Motion is T = 2*pi*sqrt(m/k) where k is ...
Cost of electricity problem2/25/2011
  Q: A professor's office refrigerator has a plate on the back that says it draws 1.1 Amp of current. ...
  A: Using the standard US house power voltage, P = E*I = 110 V*1.1 amps = ??? W Since it runs 50% of ...
question on laws of motion2/24/2011
  Q: two cells of the same emf'E'and different internal resistances r1 and r2 are connected in series ...
  A: You probably suspect, just from the symmetry, that A and B experience equal and opposite ...
definition of physic2/23/2011
  Q: what do you think about definition of physic? thanks for answer
  A: My dictionary defines physics as "the science concerned with the study of physical objects and ...
physics2/22/2011
  Q: two forces act on the 7kg block,the magnitude of the forces are 59N and 33N.what is the acceleration ...
  A: I can't say. It depends on the angles involved. If the 2 forces are both pointing the same ...
Newtonian motion2/21/2011
  Q: A raft is used in a river that varies in depth, width, and current at several points along its ...
  A: The raft is rowed at 2 m/s, aimed towards the opposite bank 200m away. Use the basic velocity ...
Ping pong balls2/20/2011
  Q: which surface do ping pong balls bounce higher on?? the surfaces are floorboards, carpet, tiles, ...
  A: The harder surfaces would provide the best rebound. Tiles may be the best but there are different ...
physics2/18/2011
  Q: I am totally lost on this question. A 5N weight is attached to the string and allowed to fall in a ...
  A: You haven't given me a good description of the setup. I'm going to guess that: the other end of the ...
Friction2/17/2011
  Q: A 10 kg block sitting on a horizontal surface is subjected to a horizontal force of 150 N. If the ...
  A: Newton's 2nd Law Fnet = m*a will give you the net force acting on the block. The net force is the ...
Displacement2/15/2011
  Q: If a car begins at a position of 10 m and drives at a rate of 20m/s for 38 seconds and then ...
  A: To do this, you need to consider 3 separate kinematic situations. 1. The car has velocity of 20m/s ...
acceleration2/14/2011
  Q: I was wondering if you could help me with a question. If a load of 240 lbs was thrust forward with ...
  A: J, I'm going to assume you meant to say "a thrust force of 13 billion pounds" because pounds is the ...
heat (newton law of cooling)2/13/2011
  Q: How will the variation in radius of the calorimeter affect the rate of cooling if the quantity of ...
  A: The rate of cooling increases with, among other things, surface area of the hot body. And since a ...
physics2/10/2011
  Q: You wake up and discover and that you are in an airplane with all the windows covered. Is there any ...
  A: And we must be assuming a perfectly smooth, straight, and level ride, if the plane is flying. And I ...
Frequency of light2/9/2011
  Q: In an answer on 4/19/2010 you said that the frequency of light on the way from a star "just does" ...
  A: Before trying to apply what you said about sound and water waves to the starlight question, I had to ...
velcoity of sound in gases2/8/2011
  Q: sir according to newton, the velocity of sound in gases is given by v = square root of (p/d) where ...
  A: I think Laplace's idea is easier to believe. The alternating C and R produces cyclic changes in ...
Physics/ Acceleration and Velocity vectors2/7/2011
  Q: Could you briefly explain how to find velocity and acceleration vectors. I am very lost in class.
  A: I'm not clear what you mean by "find" vectors. I know, when you're lost on a subject, it's hard to ...
Physics Questions2/5/2011
  Q: Can you help me on this question please? A soccer ball is kicked from the playing field at an angle ...
  A: We have to assume that the 46 m does not include any continuing bounces or rolling. Then the given ...
I am trying to fathom the forces involved in asteroid impacts2/4/2011
  Q: Good day! If an object with a mass of 1 tonne is traveling at 20,000km/h, how much energy does this ...
  A: The energy question is routine. The formula for kinetic energy is KE = (1/2)*m*v^2 where the units ...
Physics equasion2/3/2011
  Q: 20 kilometers =how many miles in written out terms dont understand how to write it out.
  A: There are 2 approaches that I'll show you. My high school physics teacher, "Doc Schwede", taught ...
physics vectors question2/2/2011
  Q: You are driving up a long inclined road. After 1.2 miles you notice that signs along the roadside ...
  A: First let's get all the units in feet. 1.2 miles * (5280 ft/1 mile) = 6336 ft Draw a triangle. ...
Hockey Puck Speed, Momentum, Kinetic energy problem2/1/2011
  Q: I am really confused with Physics and don't have older siblings to help me. I find all these ...
  A: 1– Weight and mass seem equivalent in our everyday experience. But they're not. Weight is the force ...
physics help1/31/2011
  Q: During a thunderstorm the electric field at a certain point in the earth's atmosphere is 1.04 105 ...
  A: First let me show you the normal way to show exponents here. 1.04*10^5 N/C where ^ is shift+6. The ...
temp.1/30/2011
  Q: I heard over CNN that in New York they are putting salt on the ice to make it melt faster..I thought ...
  A: It's actually the water that is with the ice that gets colder. There is a balancing act going on. An ...
two skaters1/26/2011
  Q: There are two skaters with masses of 75kg and 35kg, respectively standing 9.0 meters apart, each ...
  A: When one pulls, it puts tension on the rope. That tension acts on both skaters. It could be either ...
Gravity and Gravitation1/25/2011
  Q: I am a Gr.6 student and I am doing some research for my science fair project. I will you give you ...
  A: My reaction to your question was to say that "yes, they are the same". But I decided to investigate ...
Physics1/22/2011
  Q: a.Relative to the floor, what potential energy does a 2.5kg package have that sits on a shelf 2.2m ...
  A: a. The formula for gravitational potential energy is GPE = m*g*h where in this case m = 2.5kg, g = ...
physics1/21/2011
  Q: what is density ?
  A: The density of a substance is a measurement of what the mass would be of a certain volume of the ...
Physics1/19/2011
  Q: how do you do this problem?? A 2.3 kg gun fires a 15 g bullet at a velocity of 250 m/s.What is the ...
  A: Part 1 -- recoil velocity: The problem leaves out details. The only way to answer it is to assume ...
lester1/17/2011
  Q: A tennis player receives a shot with the ball (0.060 kg) traveling horizontally at 50 m/s, and ...
  A: Momentum = m*v. Velocity is a vector, therefore momentum is a vector. Impulse = change in ...
Physics1/16/2011
  Q: er, can you give an example to differentiate between the two methods (loop current method and branch ...
  A: Start by drawing the circuit we're going to analyze. Draw 2 horizontal lines. In between there will ...
Physics1/14/2011
  Q: A milliammeter of negligible resistance produces a full scale deflection when the current is 1mA.How ...
  A: The movement provides full deflection when 1 ma flows through it. To make the meter a voltmeter, you ...
prism1/12/2011
  Q: What is the minimum angle of deviation of triangular prism?can angle of deviation be greater than ...
  A: What is the minimum angle of deviation of triangular prism? Go to ...
Tension Problem1/9/2011
  Q: A large uniform chain is hanging from the ceiling, supporting a block of mass 49 kg. The mass of the ...
  A: It's asking for the tension at the lowest point of the chain. If the chain were hanging without the ...
Meteorological problem1/8/2011
  Q: My question is; there is a train moving to west along the equator and train's velocity is 20m/s .a ...
  A: I am confused by your subject title since this question doesn't have any relation I can see to the ...
Physics1/7/2011
  Q: A physics student pushes on a stationary soccer goalpost and measures a maximum of 120N before the ...
  A: The static friction is able to exert equal and opposite force to oppose the student's applied force ...
Finding the refractive index of water1/6/2011
  Q: Simply , my question is : HOW TO FIND THE REFRACTIVE INDEX OF WATER USING A PRISM. Note: better if ...
  A: Check out this web site. http://laser.physics.sunysb.edu/~dennis/journal/ See the entries for July ...
charges in a hollow conductor.1/5/2011
  Q: I'v asked another expert about this but I don't seem to understand. lets say a hollow a hollow ...
  A: Let me make sure what you mean by charged by induction. I will assume that the rod is brought near ...
moving electrons1/4/2011
  Q: When we move in an electric field, the potential changes at the rate of 10 Vm-1. What is the ...
  A: Two electron beams: The same force exists on electrons moving in a beam and electrons moving in a ...
DC power1/3/2011
  Q: Happy New Year ! In AC the power is the area under the EM oscillating wave.In DC there is only the ...
  A: If you set up axes with the vertical axis being voltage and the horizontal axis being current, your ...
EMP effects on the human brain1/2/2011
  Q: EMP has a very high E field, high enough to breakdown air. With a voltage of say, 30,000 volts per ...
  A: I have no expertise that applies here. I did look into levels used in psychiatric electroconvulsive ...
Energy12/30/2010
  Q: The energy in an EM wave is given by E=hc/lambda.For our transmission lines the frequency..and hence ...
  A: The energy is not limited to only one value. It is quantized in levels given by the complete formula ...
Kinematics12/26/2010
  Q: Can you pls help with this question? A photographer is taking aerial shots from a hot-air balloon. ...
  A: The kinematic formula to choose (from the standard set of 4) here is y = Vi*t + (1/2)*a*t^2 where y ...
Kinematics12/22/2010
  Q: What does the gradient of the graphs of kinematics suggest?How can it be knowm that the velocity or ...
  A: The correct interpretation of kinematics graphs depends on which graph it is. The time is almost ...
Physics12/20/2010
  Q: what is the cause of gravitational force and please make it clear
  A: Gravity is one of the basic characteristics of the universe. It is called "one of the four ...
Work and Energy12/18/2010
  Q: Consult Multiple-Concept Example 5 for insight into solving this problem. A skier slides ...
  A: I hope Multiple-Concept Example 5 wasn't important. There are 2 general ways at attack this. I'll ...
Physics Lecture Problem12/17/2010
  Q: We were given this question in class and I don't know what equation to use. An airplane at an ...
  A: They have given you some extra information to see if it will confuse you. The weight of the package ...
Calculations of Density.12/16/2010
  Q: A box has a mass of 1.6 kg., a length of 20 cm, a height of 10 cm, a width of 10 cm, what is the ...
  A: Density = mass/volume. The units are usually kg/m^3, so you need to convert those dimensions to ...
**URGENT**12/15/2010
  Q: I am in grade nine science and in class we did a lab on on current, potential difference and ...
  A: Regarding the one error source you mentioned, the ideal voltmeter would have very high resistance. I ...
Icy Hill12/14/2010
  Q: On a icy hill that has an incline of about 30 degrees for one block, can you tell me how many bags ...
  A: An incline of 30 degrees? Really? I think that would be impossible for my pickup even without ice ...
Physics Mechanics12/13/2010
  Q: A ball is thrown from the top of one building towards a nearby very tall building 50m away. The ...
  A: You need to find how much time it will take to reach the other building. Then you can use that to ...
physics12/12/2010
  Q: Consider a large crane which is being used to lift a heavy load of M = 18,000 kg. To the top of ...
  A: Since the load is being lifted at constant speed, the system is in equilibrium. All forces have ...
Physics12/11/2010
  Q: Just telling me what the formulas are for all of the problems in layman's terms would be great. I do ...
  A: 1. The plank is in a state of equilibrium, so the net force on it is zero. The mass is 0.1 kg, so ...
Physics12/10/2010
  Q: Tackle system with 5 supporting ropes loses 6% of in put to friction how far will 30 lb load move if ...
  A: With 5 supporting ropes, the tackle system has a mechanical advantage of 5. The advantage decreases ...
Physics12/8/2010
  Q: (1) If the weights of the weight hangers were exactly the same could their weights have been ...
  A: (1) I don't know. What weight hangers? What computations? (2) If the ring was not in equilibrium, ...
Physics - Rotation and Inertia12/7/2010
  Q: A uniform rod of mass M=2kg and length L=3m is connected to a uniform disk of mass md=1kg and radius ...
  A: a) My Physics book gives the moment of inertia of 2 of the 3 components of this problem. Simply a ...
physics12/6/2010
  Q: I have been testing lenses for medium impact standards for Industry, I need to know how to calculate ...
  A: There isn't enough information for me to tell you the force the lense sustains. The lens is given an ...
physics12/5/2010
  Q: use the equation for uniform acceleration to fin: 1)the taken for a car to accelerate at 2m/s2 from ...
  A: Let me show you the normal way to show exponents here. accelerate at 2m/s^2 where ^ is shift+6. 1) ...
Physics question12/3/2010
  Q: Consider the 93 N light fixture supported as in the figure. Find the tension in the supporting ...
  A: The lamp is in a state of equilibrium. That means the net force acting on it is zero. It has a ...
Physics12/1/2010
  Q: can you please help me with a conservation of energy question for homework? There is a 50kg ...
  A: I assume that the water is still, like in a lake instead of moving, like in a river. The location of ...
G force11/30/2010
  Q: I am building a centrifugal pumpkin launcher. Is there any way to determine the approximate G-force ...
  A: The obvious method of finding the G limit is testing. Other than that, I don't know. There would be ...
physics11/29/2010
  Q: A golf ball bounces down a flight of steel stairs, striking several steps on the way down, but never ...
  A: Elastic collisions conserve energy. So no energy is lost hitting the steps (or due to air resistance ...
Physics.(motion)11/28/2010
  Q: When we throw a ball upward while sitting in a (running) bus,it comes back into our hand ...but when ...
  A: When you say "when we throw it upward outside the bus", do you mean sticking your arm out the window ...
physics rotational dynamics11/27/2010
  Q: A toy consisting of two balls, each 0.45kg at the ends of a 0.46m long, thin, lightweight rod. How ...
  A: Moment of inertia is defined as I = summation of(Mi*Ri) for all i, where each mass, Mi, is a point ...
Newton's Theory of Cooling11/26/2010
  Q: A thermometer reading 7 degrees C is brought into a room with a constant temperature of 38 degrees ...
  A: Well, I can't get 15.23 either. The fraction 17/21 is less than 1 so the ln function gives you a ...
particles11/24/2010
  Q: how does a particle separate on solid and water my 13 year old has been told to write a paragraph on ...
  A: I'm not sure if this is what you mean but I found this website that talks about separating the parts ...
Physics question11/23/2010
  Q: In order to strength test a piece of glass, we need to drop a 4kg steel ball with a diameter of ...
  A: When you hold the ball above the glass, it will have gravitational energy given by GPE = m*g*h The ...
angular acceleration11/22/2010
  Q: A wheel is rotating at 180 rpm and slows down to rest in 12.0 seconds. a. What is the angular ...
  A: Convert the rpm data to radians/s. 180 revolutions/minute * (2*pi radians/1 revolution) * (1 ...
mechanics -statics11/21/2010
  Q: I have a doubt to draw the diagram for the following question, Q. A 200 kg load is suspended by a ...
  A: Yes, sketching that is tricky. My first sketch has one rope down and to the right, the other down ...
physics (inclined motion) help please11/19/2010
  Q: A 100kg box sits on a rough incline held at rest by a very thin rope attached to another hanging ...
  A: The "other hanging mass", --> I'll assume it's also on the incline and the very thin rope passes ...
Systems of Particles11/18/2010
  Q: I have this assignment question where I am given a distance between two masses and I have calculated ...
  A: This can be done with simultaneous equations. It involves recognizing that the time to collision ...
Forces11/17/2010
  Q: A 5.5 kg frog jumps straight up and lands in the same spot as before. In order to jump the frog ...
  A: That's a big frog you have there. It weighs more than a lot of cats. I need to redo what I said ...
Stability, Equilibirum and Tipping11/16/2010
  Q: Square table 0.6m long with center of mass 0.6m above the ground. What is its tipping angle? This is ...
  A: Let's draw a side view of a table with spindly legs so only 2 legs show. (The 2 legs on the far side ...
VERY IMPORTANT ! !11/14/2010
  Q: A Joule divided by a Second = a Watt kgm2/s2 divided by a Second = kgm/s3 = a Watt When you ...
  A: Let me show you the normal way to show exponents on this site. The joule in base units is ...
physics-momentum11/13/2010
  Q: I need help understanding this question and its elaboration. it's like this.. a)an empty sled is ...
  A: I edited this below in part b. a) It's true that the speed must decrease because of the additional ...
Moment11/12/2010
  Q: Determine the angle which will maximize the moment Mo of the 200-N force about the shaft axis at ...
  A: For the purposes of this problem, you could replace the arm with the bend in it with a straight arm. ...
es urgente x favorrrr es para mañana ayuedeme11/11/2010
  Q: un globo se carga negativamente al flotarlo y despues se adhiere a la pared ¿significa q la pared ...
  A: Hola lady yajure, Lo siento, mi Español no está bueno. El globo se adhiere a la pared porque la ...
Projectile motion11/10/2010
  Q: Luke is in a train which drives past a platform at a constant velocity v in s^-1. He is tossing a ...
  A: The horizontal component of the velocity is Vx, the train's velocity, where Vx = x/t and x is the ...
Physics11/9/2010
  Q: A six feet tall lady wants to see her full image in a plane mirror . What will be the minimum length ...
  A: It'll be easier to explain if I change the woman's anatomy temporarily. Let's say her eyes are at ...
Acceleration11/6/2010
  Q: A 125 N box is pulled along the floor with a force of 60N acting at an angle of 42 degrees to the ...
  A: The horizontal component of the applied 60 N force is Fha = 60 N*cos42 The force of friction, Ff, ...
Physics-Accelerated Motion11/4/2010
  Q: At the instant the traffic lights turn green, an automobile that has been waiting at an intersection ...
  A: Let me show you the normal way to show exponents here. acceleration of 2 m/s^2 where ^ is shift+6. ...
Auto Accident11/3/2010
  Q: I have a very real problem. On October 29th I was involved in an auto accident with 2 other cars, ...
  A: I'm sorry for your mishap. It is difficult to analyze accidents. There are so many variables to ...
physics11/1/2010
  Q: TWO EQUALL FORCE HAVE THEIR RESULTANT EQUALL TO ZERO.ATWHAT ANGLE ARE THEY INCLINED TO EACH ...
  A: Hell RAJEEV, Let me start off by trying to simplify this. The question asks about forces. Force is ...
Newtons 2nd Law10/30/2010
  Q: Skateboarder slides down frictionless ramp inclined at angle 30 degrees to the horizontal. He then ...
  A: ****** There are 2 different approaches to solving this problem. The principle of conservation of ...
kinematics equations for accelerating objects10/29/2010
  Q: my physics teacher makes relative velocity very difficult to think understand. do you think you can ...
  A: This can be explained with equations that are hard to grasp. They're true, but when you don't have a ...
Physics10/27/2010
  Q: I'm stuck on thisA baseball has a mass of 140 grams. If the pitcher's throwing motion takes 0.2 ...
  A: To find force, you will need to use Newton's 2nd F = m*a where you need to have m in kg, so convert ...
c.g and centripetal force10/26/2010
  Q: Why the height of racing car is kept small? what would happen if earth stops rotating around sun?
  A: car: To think about what prevents something falling over, think about hanging a pendulum from its ...
physics10/23/2010
  Q: At what point is the string most likely to break when a lead ball is being swung in a vertical ...
  A: For the ball to follow a circular path, there must be a centripetal force (towards the center) given ...
Physics-Projectile Motion10/22/2010
  Q: There is a tower 1000 m high. A ball is shot horizontally from the cannon at an initial velocity of ...
  A: If the ball is to never land, that means 8,000 m/s is fast enough that at least it continues going ...
Newton's Third Law10/21/2010
  Q: The instruments to a weather ballon have a mass of 5kg. a)What do the instruments weigh? b)The ...
  A: a) Weight on Earth, or at low altitudes, is given by the formula W = m*g where g = 9.8 m/s^2. Note: ...
balance10/20/2010
  Q: sir one question when we ride bicycle why dont we fall? What is the science behind the balancing the ...
  A: I found some websites that explain that quite well. ...
physics[oscillations]10/19/2010
  Q: a body of mass 5g is executing SHM about a point O with an amplitude of 10cm.its maximum vel is ...
  A: The instantaneous distance from point O is given by d = A*sin(w*t) ... (1) where A = 10 cm, and ...
physics10/18/2010
  Q: If an object were released in space far away from planets or stars and given an initial momentum ...
  A: Newton's 1st Law of motion says that an object in motion tends to stay in motion unless acted on by ...
Balance10/17/2010
  Q: What is the indication of balance of a passenger of mass m who stands on a cart of mass M ( the ...
  A: There are different types of balances. I'm going to assume the "balance" is of the type shown in ...
physics help please10/15/2010
  Q: ok so the question is: objects of masses m1=4.00kg and m2=9.00kg are connected by a light string ...
  A: Here are hints for the steps you need to take. acceleration of the object: Use the kinematic ...
Blocks on an incline10/14/2010
  Q: I'm confused as to how to answer this question Boxes B1 with mass 1.50 kg and B2 with mass 3.00 kg ...
  A: Notice the trailing zeros after decimal points. That's an indication that you need to maintain 3 ...
Newton's 3rd Law10/13/2010
  Q: "Sir, please help me with this homework question. I just don't understand and I have used up all but ...
  A: I'll explain what is to be done so you can understand, can do the work, and get the right answer. ...
running along side a train10/12/2010
  Q: you are running at a speed of 5.2m/s, when you are still 15m away, the train accelerates at a rate ...
  A: The units of acceleration must be distance/time^2. I will assume you meant to say that the train ...
Kinematics10/11/2010
  Q: I couldn't figure out this problem. May you help me? Thank you. Two trains start 6 minutes apart ...
  A: The 1st train went 2 Km before it reached full speed. That took part of the 6 minutes. How much? ...
motion10/9/2010
  Q: why does an apple in the coach of train does not collide to the wall of coach when it is thrown in ...
  A: A one-word answer is "inertia". Part of Newton's 1st Law says that an object at rest remains at ...
PHYSICS HELP10/8/2010
  Q: 1)A sports car crosses the bottom of a valley with a radius of curvature equal to 85 . At the very ...
  A: You don't use any units in your question. They're very important. For example, the radius in #1: ...
projectile motion10/7/2010
  Q: Romeo is tossing pebbles at Juliet's window and wants the pebbles to hit the window gently, with ...
  A: 1) The pebble rises 4.5 m before starting to lose altitude. So use the kinematic formula Vvf^2 = ...
I have no clue how to do this problem.10/5/2010
  Q: suppose you are 2m tall and standing halfway between a candle on the floor and a white vertical ...
  A: Draw a picture! View it from the side with the candle (have to assume it's a very short candle) on ...
Acceleration10/4/2010
  Q: A worker drops a wrench from the top of a tower that is 80 meters tall. How fast is the wrench ...
  A: You probably have a set of 4 kinematic formulas. If you want to find time, use this one y = Vo*t + ...
Physics10/3/2010
  Q: Why speed is directly proportional to air drag in case of falling of a body considering air ...
  A: In a strong wind, like a hurricane, objects in the wind have considerable force exerted on them. If ...
galvanometer10/2/2010
  Q: I was wondering if you could help me out in understanding how a galvanometer works? Thankyou :)
  A: When a current flows through a galvanometer, it makes a needle move. This is because it acts much ...
Regards...query on mechanics9/30/2010
  Q: Sir our four fundamental forces are conservative forces then from where does the concept of non ...
  A: When we are studying a system, we wish to keep the study simple. Consider a ball thrown straight up ...
friction,acceleration9/29/2010
  Q: sir If we are running and want to stop at once.from where the force is provided for retartation? (2) ...
  A: When you need to stop running, your legs provide the force for retardation. Your legs kind of stab ...
E=mc2 and the photon9/28/2010
  Q: If a photon has no mass (m=0), how can it have energy? Why is it affected by gravity?
  A: This is a difficult subject. The best I can do is refer you to these websites and hope you can get ...
Physics9/27/2010
  Q: why does wave length of light change during refraction but frequency remain constant? give pure ...
  A: The wave length, we use the Greek letter lambda, changes because the speed of light changes in the ...
Instruments9/26/2010
  Q: Could you please tell me 5 similarities and 5 differences between Micrometer screw gauge and ...
  A: I think it would be much better for you to study the 2 instruments and make your own lists. These ...
Determining Vehicle's Acceleration9/25/2010
  Q: How can I determine my vehicle's acceleration per second as it slid down an inclined plane ( a ...
  A: There isn't enough information to say. That would require being able to determine the net force ...
projectile9/24/2010
  Q: In the figure here, a ball is thrown up onto a roof, landing 4.20 s later at height h = 23.0 m above ...
  A: Using the tip given in the question, assume you were on the roof, and caught the ball 23.0 m above ...
efficiency9/23/2010
  Q: can you explain efficiency and how it is related to work
  A: Check out this website http://en.wikipedia.org/wiki/Mechanical_efficiency Applying your algebra ...
Vectors9/21/2010
  Q: I don't really understand the following questions, I'm having a hard time understanding vectors. If ...
  A: 1) I need to add some details to the question. I'm going to assume that A's 28 degrees is measured ...
sublime substance9/17/2010
  Q: sir i want ot ask naphtalene is a sublime substance but in many books it is given that its melting ...
  A: Whether or not a substance undergoes sublimation depends on the environment it's in. You probably ...
Weight / pressure to length.9/16/2010
  Q: I have an Articulating arm TV mount. I have a 75lb TV that's going on it. What is the calculation ...
  A: It's more complicated than you imagine. You're asking about pressure on the wall which would be ...
Physics9/15/2010
  Q: A 0.2 kg metal ball is tied to a string 0.6 m long. If the breaking strength of the string is 66.74 ...
  A: In order for the ball to go in a circle, a force called centripetal force, Fc, is required. ...
physics 11 hon9/14/2010
  Q: I actually want to learn how to do it. Here it is:two high speed trains are approching each other on ...
  A: One trick with this question would be to choose the most useful reference system. Consider yourself ...
fluids9/10/2010
  Q: a ship floating in the ocean is a familiar sight. but is all that water really necessary?. can an ...
  A: All that water is not necessary. Ocean vessels commonly cruise up the St. Lawrence and sail on the ...
wavefront9/7/2010
  Q: "as we know wavefront , thats when light passes through a medium then it vibrates particles of that ...
  A: Let's talk about sound first. If a flying bird suddenly makes a call, the wavefront of sound expands ...
magnetism9/6/2010
  Q: The radius of loop c and d is twice that of loops a and b.The magnetic field is the same for each. ...
  A: Magnetic flux is defined as the surface integral of the vector dot product B.dS where B is the ...
Physics9/5/2010
  Q: Is it possible for an object to move so that it produces an absolutely vertical line on a velocity ...
  A: No, that would not be possible. Even if it was a short vertical line, it would mean that the ...
Force in kg's9/3/2010
  Q: Is this calculation correct if I use F=m*a formula for this case? - ball weights 0,4 kg - it goes 20 ...
  A: Let's start with your question about colloquial use. Yes, I guess you can do that if you live ...
physical science8/27/2010
  Q: a runner runs 600m north, then runs 500m east what distance does she runs?
  A: As the question is worded, I would answer 1100 m. If the question asked for the displacement ...
Question on Momentum8/26/2010
  Q: You and your buddy are suddenly attacked by a 100 kg tiger. He charges towards you and makes a final ...
  A: Momentum will be conserved. The tiger possesses momentum given by Pt = mt*Vt Since your muzzle ...
Momentum8/24/2010
  Q: Sir, I have difficulty in getting the concept behind this problem. A ring of mass m free to slide ...
  A: The principle of conservation of energy would be good to use here. The system starts out with ...
What`s perpendicular force?8/23/2010
  Q: Hey Low! I`m a freshman and we`re being asked to look for a meaning for these certain forces. ...
  A: Hey Low B, Often, the terms Parallel and Perpendicular forces are used when an object is sitting on ...
Engineering8/20/2010
  Q: can you please help me A lift system consists of a cage of mass 4000kg and a winding drum of mass ...
  A: I wasn't familiar with the phrase "radius of gyration" so I had to look it up online. It's ...
applied physics / newtons second law8/19/2010
  Q: A rocket hovering in the air, must fight gravity in order to maintain it's gravitational potential ...
  A: The energy cost of a rocket maintaining altitude can be compared to the energy you would burn ...
Rocket Deceleration8/18/2010
  Q: A rocket with a mass of 2,000kg has an engine that produces a force of 400N. How long must the ...
  A: I will assume that the thrust vector points in a direction exactly opposite Vo, the original ...
Engineering Science8/17/2010
  Q: Can You please help me please A differentiator is a device that differentiates any input signal ...
  A: This problem requires that you exercise your calculus skills. The output's value is just the ...
physics8/15/2010
  Q: what makes an object tossed from a moving car, continue to follow or even past the car if the car ...
  A: A one word answer would be inertia. Mass has inertia. Newton's 1st Law applies in this case. It ...
question on current electricity8/14/2010
  Q: two cells of the same emf'E'and different internal resistances r1 and r2 are connected in series ...
  A: Ohm's Law tells us that the current I is given by I = 2*E/(R+r1+r2) If the terminals of the first ...
physics8/11/2010
  Q: If a 10j of work is used to push a coulomb of charge into an electrical field, what is the voltage ...
  A: The definition of electric potential difference is worded much like your question. You determine the ...
Mechanics: initial velocity & net force8/10/2010
  Q: I am trying to find out a particle's position x(t) and velocity v(t) for time t, given its initial ...
  A: This is much like the task of analyzing projectile motion. Consider the motion of a projectile fired ...
physics8/8/2010
  Q: communications satellites are often placed in circular orbits 3.6*10^7m directly above the equator. ...
  A: The speed of light, and all other electromagnetic radiation, is 3*10^8 m/s. Velocity is given by ...
impact force calculation8/7/2010
  Q: I'm a biological anthropology student and am researching cranial fracture patterns resulting from ...
  A: I'll show nearly all my steps because I foresee a fair chance that you may have to revise some of ...
Astrophysics8/6/2010
  Q: I just wanted to know what path would a 7solar mass star take (i.e. would it end being a white dwarf ...
  A: I didn't know -- not my field so I had to do some digging. I'll paste the URLs in here for you to ...
physics8/5/2010
  Q: what is a 2 kilograms object starts to slide down at an inclined plane when the angle of inclination ...
  A: I'm not sure about your first sentence. I'm going to rewrite it to say what I think you mean, and ...
Physics - acceleration8/4/2010
  Q: I have two questions about acceleration which I cannot solve. 1) A small sphere is attached to the ...
  A: 1) The meaning of the phrase "effective acceleration" is probably where you are having trouble with ...
investigatory8/3/2010
  Q: Sir, I have been asked to an investigatory project on "Conservation of energy in a vibrating ...
  A: If you are to demonstrate that energy is in fact conserved, it can be easily shown that it is (but ...
terminal velocity of arigid sphere falling in a liquid8/1/2010
  Q: Johnson, excuse me first to ask a long question but the answer is far brief. if we consider a rigid ...
  A: Your v(t) asymptotically approaches vmax. That means that as t approaches infinity, the value of ...
g's7/31/2010
  Q: Johnson,i can not understand g's, g is gravity of earth that i konw,i read a introducation of ...
  A: I worked in the Aerospace industry and was involved in the testing (to verify performance and also ...
Cells combination7/27/2010
  Q: What happens when a 0.75 V and 1.25 V cells are connected in series.What would be the effective emf? ...
  A: The question asks for EFFECTIVE emf. That essentially means its asking what battery emf would have ...
Simple question..7/25/2010
  Q: i have fairly simple question if u can help me out here, it says find the net charge on Q1, due to ...
  A: I'm going to assume that you meant to say the task to is find the net -force- on Q1. Both Q1 and Q2 ...
How much force is required to rotata an object?7/24/2010
  Q: I am a total novice when it comes to Physics so I was wondering if you could illuminate something ...
  A: First some assumptions: Since the rod is through its center, it will not have any direction that ...
help7/23/2010
  Q: person exerted an effort force of 250 Newtons to roll the barrel along the ramp,what is the ...
  A: OK, so you need a bit more help. Therefore, some of the steps I took setting it up were probably too ...
help7/22/2010
  Q: person exerted an effort force of 250 Newtons to roll the barrel along the ramp,what is the ...
  A: I can't give you an answer without more information. Efficiency is a ratio efficiency = energy ...
Moving object7/21/2010
  Q: why an object at a rest can be considered to have uniform motion ?
  A: My Physics book doesn't define "uniform motion". It does define "uniform circular motion" as ...
projectile motion7/20/2010
  Q: I was hoping I could get your help on the following question. It's an easy question but I haven't ...
  A: Hola Maria, This question requires that you understand that the original horizontal velocity of the ...
Physics7/19/2010
  Q: A 1.20-kg block of metal is sitting on a frictionless plane, inclined at an angle 25 degrees from ...
  A: I will leave drawing the free-body diagram to you. But here's some help. The 3 forces are 1, the ...
black color umbrella7/17/2010
  Q: why do we prefer black coloured umbrella in rainy season?
  A: I think for an umbrella it's nothing more than style or tradition. In the sunny season, it would be ...
gravity7/14/2010
  Q: i walked up hill for 20 sec and burned 7 calories i then walked for 10 minutes and burned 90 ...
  A: I will assume that the 10 minute walk was on level ground?? Also, I have to assume that you walked ...
Superconducting in space7/13/2010
  Q: I know this is a rocky start, but I would like some one of caliber to answer my questions. In the ...
  A: You say that all of those issues are solvable if we utilize superconductivity. To me that seems to ...
physics7/12/2010
  Q: An ice-skater has a moment of inertia of 5.3 kg*m^2 when his arms are outstretched. At the time he ...
  A: The same conservation of momentum principle that you have probably studied for linear motion applies ...
q factor5/7/2010
  Q: i have a problem about RCL parallel circuit . when we have a RCl circuit with applied sinsusoid ...
  A: Since the elements are all in parallel, the full applied sinusoidal voltage from the source is ...
Heat/Water Heater Problem5/6/2010
  Q: I know a few items of data that I need to have in the follow problem, including mXcXdeltaT, and ...
  A: The product m*c*deltaT yields Q, or quantity of heat with units of Joules. In general we say that ...
light speeding5/5/2010
  Q: what would be needed to turn solid matter into a laser? ANSWER: Hello G. do A., Building a laser ...
  A: do A., The first sentence in the Wikipedia article defines a laser as a mechanism. The mechanism ...
inclined plane5/4/2010
  Q: we did a practical inclined plane .we kept the angle constant of the plane.i want to know much more ...
  A: I guess I don't understand. If you keep the angle constant the only other things you can change ...
mixture temp5/2/2010
  Q: can u please tell me any formula 2 find the temperatre of mixture when 1) ice and water are mixed 2) ...
  A: 1) Let the mass of the ice be mi and the mass of the water be mw. I'm going to assume a general case ...
MA of inclined plane4/22/2010
  Q: Sir: How can i calculate MA of inlined plane in lab?is it calculated by dividing total length of ...
  A: See the first 2 formulas in this website http://en.wikipedia.org/wiki/Mechanical_advantage ...
Focal length of a lens?4/21/2010
  Q: An object is located 26.0cm from a certain lens. The lens forms a real image that is twice as high ...
  A: Since the image is real and 2X as large, the magnification m = -2. The formula m = -i/o will tell ...
refraction of light4/19/2010
  Q: sorry sir i know that this question is out of your topics but i know that you would be able to anser ...
  A: 1a) Frequency remains constant as light from a distant star arrives on Earth. And even if that light ...
Power4/18/2010
  Q: If you are traveling at 60mph (converting to m/s) and must brake to a stop in 5 seconds. How much ...
  A: Converting to 60mph m/s: 60 mph is about 96 km/hr. Converting 96 km/hr to m/s: 96 km/hr * (1000 m/1 ...
Kepler's Laws4/15/2010
  Q: I'm a student of 12th class.I've a couple of Qs regarding gravitation. 1)Are Kepler's Laws ...
  A: 1) Yes, and Earth and man-made satellite systems too. 2) A circular orbit is stable when the ...
Physics4/14/2010
  Q: Sir i m in 12th grade and very much confused by this dumb question of mine.I hope you will my ...
  A: The formula you gave would not be valid if there is an angle between the force vector and the ...
Projectile motion4/12/2010
  Q: Help is VERY MUCH appreciated. Q ) A skier launches from a ramp with a horizontal velocity of ...
  A: This is a concept that you will have to use again and again. So stay with me thru this explanation. ...
Two pulley pendulum4/11/2010
  Q: What is the physics behind the two pulley pendulum? One side is started in motion and is lowering to ...
  A: When both bobs are hanging still, the tension in the string above each is, of course, equal to the ...
Physics HELP4/10/2010
  Q: I am working on this physics prolem and have no clue what to do! A 4.5 kg object moving in two ...
  A: There are 2 methods I will offer. Using basic kinematic formulas and Newton's Laws or conservation ...
Space-to-Earth trajectory4/5/2010
  Q: Steve, Thank you in advance for volunteering your time on questions like this. My question is about ...
  A: Good job of fact checking. You are right, my result doesn't pass the logic test. I don't have an ...
accident probability of vehicles of different height4/4/2010
  Q: Could you please explain why double Decker buses accident much than ordinary buses....?? the ...
  A: I assume the types of accidents that involve double Decker buses much more than ordinary buses would ...
mass/acceleration/deceleration4/3/2010
  Q: Two objects, lets say automobiles, need to stop. One is traveling at a constant 70 MPH. The other ...
  A: One assumption I have to make: When the accelerating vehicle applies the brakes, the driver no ...
want to know about the tranmission of electricity4/2/2010
  Q: how the distribution of electricity carried from powerstation to home full explanation and in home ...
  A: A full explanation would fill a book. These 2 websites summarize the topic well. ...
Space-to-Earth trajectory4/1/2010
  Q: Steve, Thank you in advance for volunteering your time on questions like this. My question is about ...
  A: Let me start with your last 2 questions. I prefer to work in the metric system, so I'll convert from ...
Physics3/31/2010
  Q: "I need to make an experiment for the science fair showing how does the velocity of an object ...
  A: Do you have a concept of your experiment? That might have helped me make suggestions that fit with ...
3D camera rotation - problem pointing camera3/30/2010
  Q: I have a camera rotating around an object in 3-space. I've got the positioning of the camera ...
  A: Unfortunately I don't have expertise in this. But I did some searching to see if I could educate ...
Space-to-Earth trajectory3/29/2010
  Q: Steve, Thank you in advance for volunteering your time on questions like this. My question is about ...
  A: If I understand your scenario correctly, your spacecraft is approximately in Earth's orbit but ...
work and energy3/27/2010
  Q: sir i have this doubt 1) torque or moment of force has the SI unit newton metre. work has also the ...
  A: 1) The Joule is used for energy. Energy is a scalar value. Torque is a vector. To compute the work ...
Physics?3/26/2010
  Q: Divers in Acapulco dive from a cliff that is 59 m high. If the rocks below the cliff extend outward ...
  A: The horizontal velocity the diver possesses going off the cliff will continue for the duration of ...
centrifugal force3/25/2010
  Q: for god sake can you please explain what is cenrifugal force? when a stone tied to a string from one ...
  A: I think we should start with confidence that we understand centripetal the same way. I think I can ...
Physics-Kinematics3/23/2010
  Q: A boulder rolls 35m down a hill, starting from rest and accelerating at 3.06 m/s^2. The boulder then ...
  A: Conservation of energy is at work here. The original potential energy is converted to translational ...
oscillations3/22/2010
  Q: a circular disc of radius R oscillates with same time period T when pivoted at the rim or at a ...
  A: This is considered a physical pendulum. The period of a physical pendulum can be shown to be T = ...
Led lights3/21/2010
  Q: I'm not sure if this is the right place for this question. I want to make led skateboard riser ...
  A: I see a problem with that plan. You need 3 batteries to provide 3.6 V if you follow the choice of ...
Led lights3/19/2010
  Q: I'm not sure if this is the right place for this question. I want to make led skateboard riser ...
  A: More detail about the battery space would be good. You gave height as 1/2 inch. What would the ...
Velocity3/18/2010
  Q: A boy throws a stone vertically up to a man standing at a height of 2.0 meters above the boy. If the ...
  A: You were probably given a set of 4 kinematic formulas. The first part can be solved using the ...
Speed and motion3/17/2010
  Q: I was driving At a rate of 50 mph in a suburban then started to go down a hill and stepped on my ...
  A: When you go down a steep hill, you can easily speed up. The car possesses potential energy due to ...
physics3/16/2010
  Q: how can one calibrate a thermocouple and why is the temperature never the same with the temperature ...
  A: I found several web sites to refer you to. As one explanation said, it depends on how good you need ...
Spring Stiffness3/15/2010
  Q: What should be the spring constant of a spring designed to bring a 1500kg car to rest from a speed ...
  A: I assume the occupants decelerate at the same rate as the body of the car. That means there's no air ...
relativity3/14/2010
  Q: I would like to know if the speed of light is the same in both an inertial reference frame and in a ...
  A: Your simple question does not have an easy answer. A complete explanation would be very complex. Go ...
Principle behind detection of wheel presence3/11/2010
  Q: We want to know the actual principle behind detection of wheel principle based on the following set ...
  A: It seems that your question involves sensing the presence of the wheel of a railroad car on a rail ...
physics help please3/10/2010
  Q: Spaceman Spiff orbits planet X with his spaceship. To remain in orbit at 421 km from the planet's ...
  A: Following a circular path, the orbit, requires that there be centripetal force acting on Spiff's ...
duality principle3/9/2010
  Q: How are you,its me I'm back again to seek enlightenment.In quantum mechanics all matter can be ...
  A: Good to hear from you again. Your questions tend to make me work to refresh my memory. You don't ...
projectile motion3/8/2010
  Q: what effect does the force of gravity have on the horizontal velocity of the fall as a ball falls on ...
  A: For any force to have an affect on the horizontal velocity, the force must have at least a component ...
newtons law cooling2/18/2010
  Q: if the temprature of the room is 20 degrees and the temprature of water in a beaker is 89 degrees ...
  A: Newton's law of cooling says that the rate of change of temperature, dT/dt, is proportional to the ...
physics2/17/2010
  Q: (a) What are the period and speed of a person on a carousel if the person has an acceleration with a ...
  A: a) The acceleration appears to be centripetal (toward the center) rather than angular (which would ...
conceptual physics2/16/2010
  Q: A child who weighed 500 newtons was on a seesaw, and located 1.5 meters from the fulcrum,and another ...
  A: I'm not sure any work is being done. Thanks to being 2X as far from the fulcrum, the lighter child ...
general space flight2/14/2010
  Q: Correct me if i'm wrong, but according to the law of conservation of momentum, velocity cannot ...
  A: In the general case, what you say, "velocity cannot change(at non-relativistic speeds) in an elastic ...
Compressing Air2/10/2010
  Q: I'll try to be brief. Can a large shop type compressed air tank, 18" diam X 48" long, be filled by ...
  A: Can a compressed air tank be filled by using a hand held pump? The quick answer is yes. But then ...
math question2/9/2010
  Q: a train is going west at 15 mph and the wind is blowing from the north east at 8 mph how fast and in ...
  A: The direction of the velocity of the smoke will change over time. It'll start out ejected upward ...
Solenoids, ferrofluids, and damping (oh my!)2/8/2010
  Q: I'm trying to design an experiment on ferrofluidic damping and how it changes with the strength of ...
  A: Ferrofluids were something new to me so I had to do some study. Now that I have an idea of your ...
physics2/6/2010
  Q: I do not understand the concept of finding the velocity,potential, or kinetic energy. My teacher ...
  A: The principle of conservation of energy is a very useful tool in physics problems. One common ...
physics2/4/2010
  Q: an engineering student standing on the edge of the roof of 10 m high building throws an egg with a ...
  A: Separate the original velocity into vertical and horizontal components. Vv = 15 m/s*sin37 Vh = 15 ...
Light leaving a lens2/3/2010
  Q: I'm not an optics major (but I have an engineering degree) and have a question on light leaving a ...
  A: I also have not made a particular study of optics. But there definitely are formulas in the field of ...
high school physics kinematic2/2/2010
  Q: "In 1Km races, runner 1 on track 1(with time 2 min, 27.95s) appears to be faster than runner 2 on ...
  A: Suppose you worked at a fruit market and were asked to weigh a bag of apples. The scale you used ...
newtons law of cooling2/1/2010
  Q: For a hot water cylinder the thermostat is set to a maximum temperature of 80degreescelsius, it then ...
  A: I refer you to the website http://en.wikipedia.org/wiki/Heat_transfer#Newton.27s_law_of_cooling One ...
high school physics kinematic1/31/2010
  Q: "In 1Km races, runner 1 on track 1(with time 2 min, 27.95s) appears to be faster than runner 2 on ...
  A: Your work is pretty good. It assumes that L1 is accurately laid out to 1 km. If you assume L2 is ...
Photons1/30/2010
  Q: Consider yourself to be a photon moving away from the earth into outer space. Will you be surrounded ...
  A: As you sit in your classroom you would say that you are surrounded by light. Actually the light you ...
electricity and potential differences1/29/2010
  Q: There is an electron is placed midway between two parallel conducting plates which are attached to ...
  A: The relationship of d, the distance between the plates; V, the potential difference between them; ...
resistance1/28/2010
  Q: I have one question. we all know that copper is a better conductor than iron. Now in text books it ...
  A: Current is the drift of a host of electrons in one direction. It not a case of steady and equal ...
Non Perpendicular force applied to a lever1/26/2010
  Q: Alright, I've read that the equation for the forces applied on a lever (F1D1=F2D2) only work with ...
  A: Yes, your first statement is true. You provide a 'torque' when you attempt to make something rotate ...
The Newton of Force Equation1/25/2010
  Q: Alright, we know that 1 Newton of force is enough force to accelerate a mass of 1 Kg to a speed of ...
  A: Your suspicion is correct. This is Isaac Newton's 2nd Law. The formula that expresses it is F = m*a ...
The collision of two metal balls1/24/2010
  Q: I used two metal balls to collide. On the table, I set one of the metal balls covering it with a ...
  A: It seems that you demonstrated where some lost energy went. Understand that it's hard to be certain ...
Physics Help1/22/2010
  Q: Two cars leave a stoplight, one 0.4518 s before the other. The second car accelerates with twice the ...
  A: a) The trick here is to make use of the fact that the distance traveled by both is equal. Use the ...
optics1/21/2010
  Q: sir, My brother asked me one question on concave mirror. In his textbook for the proof that focal ...
  A: I agree, not clear. I could try to explain myself with figures and three-part harmony, but I found a ...
help please1/19/2010
  Q: Johnson, can you help me A rod has a charge of -2.0 µC. How many electrons must be removed so that ...
  A: Now what do you mean by -1.6 10-6? Looks like -1.6 add 10 subtract 6 = +2.4. Ohhh, wait, do you ...
optics1/18/2010
  Q: sir, My brother asked me one question on concave mirror. In his textbook for the proof that focal ...
  A: This was a good challenge. I hadn't done geometry for ages. You have the parallel lines PC and the ...
help please1/17/2010
  Q: Johnson, can you help me A rod has a charge of -2.0 µC. How many electrons must be removed so that ...
  A: Rod: So the charge needs to change in the positive direction by 9 µC. To do that, electrons will ...
bouyancy1/15/2010
  Q: Are weaker muscles resisted by buoyancy? Are stronger muscles assisted by buoancy?
  A: The affect of buoyancy on a chore that muscles are trying to accomplish depends what chore those ...
Physics Pressure1/14/2010
  Q: In a sample of seawater taken from an oil spill, an oil layer 6.0 cm thick floats on 52 cm of water. ...
  A: My book says that the density of seawater is 1.03*10^3 kg/m^3. Notice how I showed the exponent. ...
Recoil speed1/13/2010
  Q: An astronaut hurls an asteroid at 100 m/s. The asteroid is a thousand times more massive than the ...
  A: Wow, that's a really strong astronaut. But I can't make sense of the sentence "The astronaut is seen ...
electromagnetic induction1/12/2010
  Q: My question is that could we deflect an electron at rest by magnetic field
  A: For an electron to be "deflected", a force must have been exerted on it. A magnetic field can exert ...
Force Problems with Kinematics1/10/2010
  Q: I am traveling along a level road at 10m/s in my 1500kg car. If the car stalls and coasts to a stop ...
  A: The car possessed kinetic energy given by KE = (1/2)*m*v^2 where m is the mass in kg and v is the ...
physics1/9/2010
  Q: How will the complete absence of air resistance affect the lives of people?
  A: Some changes will be positive, some negative. Negatives include: * Parachutes won't work anymore. ...
physics1/7/2010
  Q: please give me some innovative ideas of making working models
  A: I have made only 2 working models -- that I can remember. The first was an airboat. It was modeled ...
Torque1/6/2010
  Q: Johnson. I was asked to design a steel sliding gate. I wanted to calculate the torque that is needed ...
  A: You didn't mention the radius of the wheel. If the radius is 0.05 m and the motor drives the wheel ...
Electrical measurements1/5/2010
  Q: I'm an engineering student. Our teacher taught us that the range of an electrodynamometer voltmeter ...
  A: I searched extensively for a discussion of these meters. I'm sorry, I haven't found anything to ...
forces1/4/2010
  Q: a mass of 200kg is dropped on to a pile of mass of 1000kg from a height of 2.5m and drives it into ...
  A: A) At a height of 2.5 m, the mass has potential energy PE = m*g*h Immediately before impact, that ...
Friction1/3/2010
  Q: The coefficient of friction between the ground and wheels of a car moving on a horizontal road is ...
  A: No, in this case the friction is required to help the car accelerate. The reason for your confusion ...
Friction1/2/2010
  Q: The coefficient of friction between the ground and wheels of a car moving on a horizontal road is ...
  A: The maximum forward force the car can apply to the road without the tires spinning is limited by the ...
question pertaining to spinning magnet1/1/2010
  Q: I am trying out on a model for my project using a mechanism to spin round magnets Magnet size: N52 ...
  A: I don't know how you have this set up, but if my guess is good I see some problems with your setup. ...
physics12/31/2009
  Q: i am in class 9 , i have to make a physics working model on motion which can be made in 1 hour only ...
  A: A very simple one came to mind first. With some string and any kind of small mass you could make a ...
air velocity affect on temperature12/30/2009
  Q: Does merely increasing or decreasing air speed really increase or decrease temperature, or does it ...
  A: If you're referring to the wind chill, you have misinterpreted what the weatherman says. The wind ...
physics12/29/2009
  Q: what is the difference between 'g' and 'G' in reference with gravity
  A: The G comes from Newton's Law of Universal Gravitation. He said that the attractive force between 2 ...
stationary particles12/28/2009
  Q: My question is about particles is steady-state - stationary particles. What will happen with a ...
  A: I have had some trouble reading your question. Perhaps due to typographical errors in some critical ...
decay of matter12/27/2009
  Q: Sir, I would like to know why materials biological and non-biological decay or disintegrate over ...
  A: Thermodynamics declares that systems deteriorate from orderly to disorderly. Never the other way ...
Punkin Chunkin Barrel length12/21/2009
  Q: Has anyone heard of Punkin Chunkin in Delaware? Well we are building an air cannon to shoot the 8-10 ...
  A: I will convert everything to SI -- meters etc. It's easier for me to do physics work in the metric ...
current12/19/2009
  Q: What is the difference between potential and potential difference in an electric circuit?
  A: I'll start with the general meaning of potential difference. Technically the definition of the ...
Physics liquid Fresh/ Salt Water Balloon Test12/18/2009
  Q: I'm working with my son on a school project. I would like to know how to figure out Density, ...
  A: Differences in density explain why a ton of cotton is so much bigger than a ton of lead. Density is ...
Time for two different objects12/17/2009
  Q: "I have a car, which velocity is 0.34m/s, i have a ball which velocity is 2.4m/s. The ball is on a ...
  A: There are some things that are not clear. To complete the scenario, I will assume that the car ...
Elastic Potential Energy12/14/2009
  Q: What is the calculated potential energy in a wood ringette stick that is 1.5m long, weighs 500grams, ...
  A: You're asking about potential energy so I'm going to assume the mention of the average velocity is ...
Need physical concept of the Vector12/13/2009
  Q: We have read the vector, its resolution,its dot product and its cross- product. Where are the ...
  A: OK, here are examples of situations where you would use resultant vectors, dot products and cross ...
electrostatics12/12/2009
  Q: electrostatics hello please tell me, during the accumulation of a surface electrostatic charge do ...
  A: The skin effect is a phenomenon that applies to AC current -- and is more significant with higher ...
Physics12/11/2009
  Q: While on a trail, a mountain biker encounters a sandy patch that is 7.1 m long. The speed of the ...
  A: I will assume the rider was going at a constant speed approaching the patch and keeps the throttle ...
Environmental Science12/10/2009
  Q: If the d.c. voltage applied to a d.c. load is doubled while the current and the time the circuit is ...
  A: Power is given by the formula P = I^2*R Using Ohm's Law, you can form other expressions for power. P ...
Light beams12/9/2009
  Q: When a light arrives on Earth from a distant planet, how is it that we can still see it? If the ...
  A: One difference between water coming out of your hose and light from a distant planet: The water ...
Snapping, Clapping, Whistling12/8/2009
  Q: I've been trying to compare the physics of snapping, clapping, and whistling as my physics class ...
  A: This page gives a good discussion of whistling. http://en.wikipedia.org/wiki/Whistling I might add ...
Simple Harmonic Motion12/7/2009
  Q: I have to build a functional object that uses simple harmonic motion. I need help thinking of an ...
  A: The first thoughts I had perhaps are obvious. Any kind of time-keeper -- from antique clocks (such ...
momentum conservation12/5/2009
  Q: A dog of mass 5kg is standing on a flat boat so that he is 10m away from the shore.He walks 4m on ...
  A: It seems that the dog is still on the boat, so the distance between the dog and boat is still zero. ...
tension12/4/2009
  Q: a 250 kg crane with an arm length of 6 meters is attached horizontallyto a building. a cable is ...
  A: You make use of the fact that the crane and the bricks are in equilibrium. That means that nothing ...
Frictional force12/1/2009
  Q: Frictional force is always_____________in the direction of motion.(Perpendicular/Opposite) (with ...
  A: "Opposite" goes in the blank. Explanation: Consider that you're standing in a lake near shore with ...
tension / forces11/30/2009
  Q: a mechanical device known as a TIRFOR using a 3/8 inch cable - 9mm - is attached to two columns 10 ...
  A: The weight hanging from the middle of the cable must cause the horizontal cable to stretch. The ...
Van de Graaff generator top and a magnet11/29/2009
  Q: simple eg: negatively charged Van de Graaff generator top and a magnet. Put magnet near top. Would ...
  A: There's no interaction if the charges are not moving (no current) and there's no motion of the ...
acceleration & tension11/28/2009
  Q: I've been trying to tackle my physics homework however am majorly struggling. 3. Three blocks of ...
  A: 3a. That force has to accelerate all three blocks, so the total mass needs to be considered in using ...
Physics - Sound waves11/27/2009
  Q: Mr. Johnson, In a question I'm working on, I am given this function: y = (0.45) sin (8.0(pi)t + ...
  A: I agree with your amplitude but disagree with your frequency. Consider a fixed value for x and just ...
Radiations11/26/2009
  Q: sir few more questions on radiations 1) In green house effect glass allows only short wavelength ...
  A: 1) This question required that I do some study. Your question seems to have it slightly wrong. See ...
Free falling motion problem11/25/2009
  Q: I got stuck up with this problems and I tried many times how to figure out why these are the answers ...
  A: Drop) You gave the kinematic formula for distance a little wrong. It's d = Vo*t + (1/2)*a*t^2 ...
acceleration11/23/2009
  Q: I've got a question about the internal combustion engine. The piston has a displacement of 10 cm. ...
  A: I never thought in detail about it before, but now I see that this motion is quite complex. If you ...
Physics11/21/2009
  Q: A nucleus of an atom has a radius of 4^-15m and 26 protons. Calculate (a) the magnitude of the ...
  A: This looks like an iron nucleus but I think you gave the radius and separation wrong. I will assume ...
radiation11/20/2009
  Q: sir in my textbook it is written that when heat is transmitted through a medium by radiation, it ...
  A: Your question indicates some error in your thinking about the meaning of the term medium. But it ...
inclined frictionless plane minimizing travel time11/19/2009
  Q: Rock sliding down a frictionless ramp of height H, and distance from the base x, initial velocity vo ...
  A: I have some problems understanding your question. I used my best guess and rewrote the problem. This ...
centre of mass11/18/2009
  Q: I read in a book that if the barrel of a gun is inclined at an angle of 45 degree with horizontal ...
  A: That would be a strange outcome if the bullet doesn't emerge on the path it was on when it was in ...
Uniform Circular Motion11/17/2009
  Q: a 600kg racing car travels at a constant speed around a circular track with a radius of 50.0m and ...
  A: In order for the car to follow the circular track, it needs to have centripetal (meaning pointed ...
floatation11/16/2009
  Q: can you verify the third case in principal of floatation in which body floats above the surface of ...
  A: Yes, that is true. Here's a way to think about it that might help it make sense. Imagine that you're ...
computational fluid dynamics11/15/2009
  Q: what are mathemtical concepts for this subject .learning matlab is sufficient or compulsory c++,c ...
  A: This topic is beyond my expertise. However I'm pretty good at searching the web. Check these sites. ...
could you please help me!11/13/2009
  Q: 1. When an athlete is preparing to throw a shot put ball, does the ball exert a force on the ...
  A: 1. Yes it does. While preparing to put, and while putting too. Consider a book sitting on a scale. ...
quantum11/12/2009
  Q: I know under the rules of the quantum, when we observe a particle we change it. But, how do we know ...
  A: Your brief statement of "the rules of the quantum" is a oversimplification. As I said in my profile, ...
capacitor11/10/2009
  Q: i am studying electronic engineering but this is my first year and i have a question about capacitor ...
  A: I was picturing a big enough swing that the dielectric was passing through and out the other side. I ...
Physics11/9/2009
  Q: A 2.96 kg particle has a velocity of (2.94i - 4.02j ) m/s. (a) Find its x and y components of ...
  A: Bell, a) The x component of its momentum = m*Vx = 2.96 kg*2.94 m/s The y component of its momentum ...
kinimatics11/8/2009
  Q: A) If the coefficient of friction between a 35-kg crate and the floor is .30, what horizontal force ...
  A: If the speed is to be steady, the acceleration must be zero. Therefore the net force must be zero ...
capacitor11/6/2009
  Q: i am studying electronic engineering but this is my first year and i have a question about capacitor ...
  A: Perhaps I'm not interpreting it the way you mean. If I've got the wrong picture, please send a ...
What is the driving force for electron to flow11/5/2009
  Q: We have read that electron flows by the electro-motive force (emf) through conductor. We also know ...
  A: 1) The units of emf is the volt, which is equivalent to Joule/coulomb. Emf is closely related to ...
Physics11/3/2009
  Q: A block of low density plastic foam and a block of lead each of mass 0.2kg are released together and ...
  A: Without more data, you can't get a numerical answer for either question. i) Ignoring air drag, the ...
Modern physics11/2/2009
  Q: Suppose that the average power consumption, day and night of an average house is 2800W. What mass of ...
  A: Fission: At a rate of 2800 W, the energy consumed per year would be 2.800 kW * 365 days * 24 hr/day ...
physics11/1/2009
  Q: 1.how the displacement of averticaly thrown ball varies with time? 2.how the velocity of verticaly ...
  A: 1. The displacement is given by the kinematic formula y = Vo*t + (1/2)*a*t^2 where Vo is the ...
emf induced in solenoid10/31/2009
  Q: Imagine that you want to wind a solenoid that would be able to keep a 10-ohm light bulb lighted for ...
  A: What you have is an RL circuit. If the light stays lit after the battery is disconnected, it's ...
Thermodynamic arrow of time10/30/2009
  Q: As time passes, physicists say the energy in the universe becomes unusable or disorganized. This ...
  A: The Second Law of Thermodynamics is based on randomness. Application of the law is valid when taking ...
mechanics10/29/2009
  Q: i cant get this problem : a short hollow steel tube (Length 30") is filled with concrete. the ...
  A: The steel tube and the concrete will share the reaction to the axial force. As they do this, they ...
resultant reactions10/23/2009
  Q: two man applying forces in different direction on a stone of mass 30kg and five healthy man applying ...
  A: Your questions deal with Newton's 3rd Law. The 2 man case: The reaction force can be thought of 2 ...
Coil Voltage/Amperage10/22/2009
  Q: I have been looking all over the Internet and cant find an answer to what I'm wondering. I know ...
  A: The induced emf will be equal to the negative rate at which the magnetic flux through the loop is ...
physics10/20/2009
  Q: Question 1: A 3.0-g bullet traveling at 350 m/s hits a tree and slows down uniformly to a stop while ...
  A: Question 1: You could do this 2 ways: * The bullet decelerated from 350 m/s to 0 m/s while going ...
Physics motion10/19/2009
  Q: A pitched ball is hit by a batter at a 40° angle and just clears the outfield fence, 99 m away. If ...
  A: I assume the 40 degrees is measured between horizontal and the original flight direction. The ball's ...
Impact Pressure of air10/16/2009
  Q: How many PSI of pressure does an RV with a front wall measurement of 8' tall and 8' wide experience ...
  A: An expert in Civil Engineering may be more familiar with the analysis of this. I did some study and ...
Physics Questions10/14/2009
  Q: "This isn't an assignment. It was a project. My teacher said we can find answers using the net. 1. ...
  A: 1. Bedsores develop as a function of the pressure the person is given by the mattress. A waterbed ...
Physics Vector problem please help10/8/2009
  Q: A hunter wishes to cross a river that is 1.8km wide and that flows with a speed of 3 km/h. The ...
  A: The hunter will have to point the boat upriver in order to achieve crossing directly across the ...
atomic physics10/7/2009
  Q: when cathode rays strike with particularly anode then why X-rays produce and only X-rays can ...
  A: As my profile says, atomic physics is not my area of expertise. However I have found some websites ...
motion10/6/2009
  Q: A heavy iron bar of weight W is having its one end on the ground and other on the shoulder of a ...
  A: The bar is in equilibrium, so the sum of the upward forces delivered by the ground and the man must ...
physics10/4/2009
  Q: if the first condition of equilibrium is satisfied on a moving body but the sum of external torque ...
  A: The 2nd condition of equilibrium is that the body's angular acceleration is zero. If the sum of ...
Frequency x ?10/3/2009
  Q: Frequency x ? I am so excited about this question, For the sake of the question let's ...
  A: Originally A*Z = c. So you can also say that Z = c/A The "Orbit Time of the Particle" is equal to ...
Physics10/2/2009
  Q: Johnson, I have been working on this question for a while now and haven't been able to figure out, ...
  A: a) The vertical component of the bike's initial 33.5 m/s is Vvi = 33.5 m/s*sin18 = 10.3 m/s So the ...
Could you please help me?I'm struggling,just want to learn from someones explanation10/1/2009
  Q: 4.)) Aisha and bert are running at constants speeds, Aisha at 9.0 m/s and Bert at 8.5 m/s. They ...
  A: These problems require that you have a good understanding of the units that speed is measured in. It ...
pulleys9/21/2009
  Q: I have two shafts.Shaft A is turning 540 rpm it has a 30 inch diameter pulley.What size pulley do I ...
  A: This is easy to understand once you see the benefit of considering the motion of the belt. Consider ...
Gravitational field9/20/2009
  Q: Do you know any websites that have computer simulations that presentation of theoretical predictions ...
  A: I know this took too many days. My Java didn't work and fixing it was a major task. I found several ...
Interference9/19/2009
  Q: a plate of thickness t made of a material of refractive index u is placed in front of one of the ...
  A: Perhaps it is due to the lack of a sketch, but as understand the situation, I agree with you. With ...
physics9/18/2009
  Q: A superhero flies 307m from the top of a tall building at an angle of 26 degrees below the ...
  A: This is an exercise in trigonometry. Draw it, just approximate the distances you don't know yet. I ...
physics question9/17/2009
  Q: I am having trouble with a physics problem, and I can't find a similar one to model when finding the ...
  A: a) This takes advantage of the concept that you can separate vertical motion from horizontal motion ...
Physics: Equilibrium Problem9/16/2009
  Q: There are two charges with masses of 10 grams each. They are suspended by strings of 1 meter long. ...
  A: I assume the strings are tied off at the same hook and the angle is 4 degrees from one string to the ...
physics9/15/2009
  Q: A parallel plate capacitor has a capacitance of 6.3 µF when filled with a dielectric. The area of ...
  A: For the case of a parallel plate capacitor with no dielectric, is described by the relationship C = ...
physics9/14/2009
  Q: A small sphere is kept on a concave glass of radius of curvature R placed on a horizontal table . ...
  A: For simple harmonic motion to be displayed, there must be a restoring force (which tends to return ...
Ohm's law9/13/2009
  Q: I'm recently doing a lab report on Ohm's law. I wonder what are the sources or error and ...
  A: Discussion of error sources you want to recognize and minimize: * The deviation from perfect ...
Oscillation9/12/2009
  Q: Describe practical examples of forced oscillations. Thank you
  A: Forced oscillations can be considered to include the process of pushing someone on a playground ...
physics9/11/2009
  Q: Identical +6.91 µC charges are fixed to adjacent corners of a square. What charge (magnitude and ...
  A: Identical: The potential at any point would be equal to the sum of potentials at that point due to ...
physics9/10/2009
  Q: what is the extended and regular body of a center of mass? what is the extended and regular body of ...
  A: The way your questions are worded, I'm not sure what you mean. I will assume this is what you meant ...
Mechanics- Forces9/9/2009
  Q: Could you please help me. How do i find the height an object has fallen from if i am only given the ...
  A: If the object was dropped from height h, the acceleration it experiences is due to gravity. Normally ...
physics9/8/2009
  Q: Could you help me give a mathematical explanation on Projectile motion?
  A: In most of these problems, the projectile is launched with an original velocity that points ...
Superposition9/3/2009
  Q: Describe experiments which demonstrate stationary waves for microwaves & stretched strings. If ...
  A: Stretched strings: The Wikipedia site discusses stationary waves. Expand the 2nd figure in the group ...
mechanics9/1/2009
  Q: SIR, A BLOCK IS ATTACHED TO TWO STRINGS WITH THE HELP OF PULLEY AS SHOWN IN THE FIGURE.THE TWO ENDS ...
  A: My first quick attempt at this gave me the result V*cos(theta). But that doesn't pass the test of a ...
color8/31/2009
  Q: what colors of ink do color ink jet printers use to produce a full range fo colors? do the colors ...
  A: The colors are cyan, magenta, yellow and black, commonly abbreviated CMYK. The ink absorbs ...
mechanics8/30/2009
  Q: I'm trying to convert units of torque. I have a mini dc motor that says it produces 5.3 g/cm how ...
  A: First I need to correct the units. The units of torque is force times distance -- example ft*lbs. ...
Physics8/29/2009
  Q: A satellite is lunched in a direction parallel to the surface of the earth with a velocity of ...
  A: Check out the figure in the section titled "Understanding orbits" in the following site. ...
PHYSICS- Laws of Motion8/28/2009
  Q: 1. A 910kg car is speeding at 97km/hr on a level road. Determine the horizontal breaking force ...
  A: It appears that you beginning study of physics. So I inserted an explanation you might need to my ...
Vectors8/26/2009
  Q: Could you please tell me- if two vectors have the same coefficient but different units, then do they ...
  A: Vectors have both magnitude and direction. Magnitude includes the units. Therefore 4 meters and 4 ...
Expeiment for project8/25/2009
  Q: i have a project in school. in that i have to make soe grphs and do some calculations for the expt ...
  A: To do this project, you need to understand the main difference in the characteristics of the 2 ...
radiation8/24/2009
  Q: we are a group of teachers . we would like to ask you this question in wars some countries used new ...
  A: If by "new", you mean developed in the last 30 years, I don't know of the weapons you refer to. And ...
Power/Velocity relationship and reference frames8/23/2009
  Q: I'm having some difficulty accepting the basic relationship between power and force, given as power ...
  A: The basic definition for power is that it is the rate at which work is done: P = W/t Note that the ...
Electromagnet vs headphones8/21/2009
  Q: Could an electromagnet interfere with ordinary operating headphones? If so, how strong/large would ...
  A: Yes, an electromagnet could interfere with ordinary operating headphones. But a mobile phone could ...
Accelerometer8/20/2009
  Q: Johnson I am building an application (for personal use) for my mobile phone that uses the build in ...
  A: Some general comments first. Accelerating from zero to 100 km/hr in 10 seconds would require average ...
chemistry8/19/2009
  Q: Q1. Calculate the mass ratio of the following properties for 1.0 Kg of air versus 1.0 kg of iron at ...
  A: I don't know what you mean by "mass ratio". To Wikipedia, mass ratio is a measure of the ...
What is the real formula for a doorknob/handle.(using physic & A LOT OF DETAIL)?8/17/2009
  Q: What is the real formula for a doorknob/handle.(using physic & A LOT OF DETAIL)? I am trying to find ...
  A: Since you didn't say, I will assume that you want a formula that gives the relationship between ...
pitch angular8/14/2009
  Q: i have a buoy with 6 degrees of freedom. i want to know a relationship between ocean wave height and ...
  A: A few assumptions: I assume you meant roll instead of row. I will approximate wave shape as ...
free fall8/13/2009
  Q: A human free fallilng can reach velocity in excess of 130mph.How do they breathe wil air rushing so ...
  A: Interesting question. And interesting answer. I had to search for it -- otherwise I would have waved ...
Light8/10/2009
  Q: If the image formed in a plane mirror is virtual how are we able to view it?Is reflection different ...
  A: You appear to see the object behind the mirror. But the object is really on your side of the mirror. ...
Rainbow8/3/2009
  Q: How the water droplet or a prism is able to separate the white light in to 7 colors? How the UV and ...
  A: Rainbow: All electromagnetic radiation travels at the speed c when it's in a vacuum. Air is almost ...
First law of thermodynamics7/29/2009
  Q: I'm on a work placement for my college course. I've been asked to find the time it takes one of the ...
  A: For the oven to cool down, heat must fight it's way through the oven's insulation to the oven's ...
generators7/28/2009
  Q: how does a dynamo work? where is it located?
  A: The discoveries that led to Faraday's Law are the foundation for the operation of a dynamo. See the ...
pls. help me ^_^7/27/2009
  Q: a piano weighing 600 lbs is to be raised to a platform 4 ft high by a plank 10 ft long. If the ...
  A: I assume that the piano is to be moved at constant velocity. Therefore, no acceleration, therefore ...
Power Problem7/9/2009
  Q: An electric heater is operated by applying a potential difference of 50.0 V to a nichrome wire of ...
  A: a) The current that would flow is given by Ohm's Law I = V/R where V = 50 volts and R = 8.00 ohms. ...
FM/AM Transmitter and receiver7/8/2009
  Q: I am having trouble hearing the minister's sermon at church. I am using their headphone, but still ...
  A: You say you are using the church's headphone? Is it the kind of system where the pews are wired with ...
Regarding Electric field and point charge!7/7/2009
  Q: Johnson, This is what's given: In a rectangular coordinate system, a positive point charge q ...
  A: 1) At any point, the existing field would be the vector sum of the individual fields produced by the ...
velocity of rain water7/1/2009
  Q: whatis the velocity of rain water? what is the velocity of water flowing from a slope of 15 degrees.
  A: Sorry this answer is overdue. When things fall far enough through air, there is a maximum speed they ...
terminal velocity6/27/2009
  Q: Is the impact of an falling object at terminal velocity greater on water or ground? In other words, ...
  A: In the 2 cases, the momentum at impact (mass times velocity) would be the same. And in both cases, ...
electrostats6/24/2009
  Q: what is the name given to charges which goes inside the earth when a conductor is charged by ...
  A: Let me describe a scenario. Imagine some wire bent so that it makes 350 degrees of a loop. The loop ...
physics6/23/2009
  Q: In ionosphere ,when sun light strikes on a air particles which phenomena occur?
  A: The ionosphere gets its name from the phenomenon of ionization. I did a search [ionosphere sunlight ...
physics6/21/2009
  Q: A car (mass 3M) has a maximum acceleration of 3 m/s2. What would be the car's new maximum ...
  A: First, the accepted way to show an exponent when you can't do a superscript: 3 m/s^2 (to get the ^, ...
physics6/20/2009
  Q: i tried to find the exact answer but i did't get succeed. what changes occur in the refractive index ...
  A: I found a graph of the changes in the index of refraction of fused quartz versus wavelength. Here's ...
physics6/19/2009
  Q: Block 1 (m1 = 1.5 kg) is on the surface of a table as shown in the figure. The rope attached to the ...
  A: 1) The figure given is a good starting point for a free body diagram. Typically a free body diagram ...
investigatory project in Physics6/18/2009
  Q: Greetings! Can you give me ideas about invesigatory project relating to Physics for high school ...
  A: I think it would be best for your project to be on a subject that interests you. Allexperts.com has ...
investi pros6/17/2009
  Q: could i just ask for a very interesting investigatory project regarding either physics., chemistry, ...
  A: I think it would be best for your project to be on a subject that interests you and matches your ...
Light6/16/2009
  Q: Light waves from the sun is unpolarised and can oscillate about its E-field axis.Is this true for EM ...
  A: I'm not sure how you mean "can oscillate about its E-field axis". The E and B fields oscillate (or ...
physics6/15/2009
  Q: A stone is thrown downward with a speed of 13 m/s from a height of 13 m. (acceleration due to ...
  A: a) The kinematic equation (one of 4 you were probably given recently) Vf^2 = Vo^2 + 2*a*s is the ...
kinetic theory6/14/2009
  Q: If L be the mean free path of a gas molecule in a gas , which is the mean free path along an ...
  A: The mean free path will still have a length L. That's if I'm interpreting the question the way you ...
Capacitance6/13/2009
  Q: Two capacitors of capacitances 22*10^-6F & 47*10^-6F are connected in series with a constant 24V ...
  A: a) The equation for finding equivalent capacitance when you have series capacitors is like the one ...
physics6/11/2009
  Q: a refractive index of 'A' is 1.41 and 'B' is 1.60 State which medium is denser? In which medium the ...
  A: The refractive index of a vacuum is 1.00. That's the least optically dense 'material'. As you ...
gravity6/10/2009
  Q: If I can jump vertically upwards with an initial velocity of X m/sec and I can reach y meters on ...
  A: First let's try to determine the forces involved during the push-off for the jump on Earth. Looking ...
steam and turbines6/9/2009
  Q: steam enters a turbine at 1300.000kPa, dry and saturated. The steam is exhausted from the turbine ...
  A: I assume that pressure data is gauge pressure, the difference between atmospheric and the pressure ...
Transition Energy6/8/2009
  Q: Take a Hydrogen atom with electron in first shell......... its energy would be equal to -2.18 X ...
  A: This is an interesting question -- one I had to study to try and answer. As my profile says this is ...
Physics of satellite orbits6/7/2009
  Q: Typical explanation: Sufficient tangential constant velocity {not an acceleration)in combination ...
  A: I think what you're missing is basically that the earth is a sphere and what that means to the ...
flux linkage and permeance6/6/2009
  Q: I'm having a bit of trouble trying to understand the difference between flux linkage and permeance. ...
  A: Permeance, P, is the inverse of reluctance, Rm. (I'm using Rm for reluctance because I can't select ...
resistance6/5/2009
  Q: To make 1 ohms resistance,temperature should be 1)0 2)Moderate 3) High 4) Low
  A: That depends on the material you're working with. For instance if you had a 1 meter long piece of ...
Frictionless6/4/2009
  Q: How are you? If i push a book resting on a frictionless surface..assume no other forces exist,then ...
  A: I'm doing well, good to hear from you. The easy answer is yes ... approaching the speed of light. ...
peltier effect6/3/2009
  Q: sorry sir i am asking this question after asking what is seebeck effect. i want to know that why ...
  A: The Peltier effect is the compliment to the Seebeck effect. Explaining is very difficult. I found ...
seebeck effect6/2/2009
  Q: sir can you explain what is seebeck effect ? i tried to find out through net but unable to ...
  A: Look at the diagram on this site. http://en.wikipedia.org/wiki/Seebeck_effect#Seebeck_effect Not ...
Mechanical advantage of compound pulleys6/1/2009
  Q: I'm having some trouble finding information about the mechanical advantage of additional pulleys ...
  A: Let's talk about the 2 pulley 200/50 system first. This gives you a 4:1 gain in load rotation speed ...
Differences in electric field5/31/2009
  Q: What are the differences between electric and magnetic fields?Many thanks
  A: A single charge can set up an electric field that just radiates out to infinity. There is no such ...
physics5/21/2009
  Q: please tell me the answer to it 1) two oppositely charged conducting spheres of magnitudes supose 3C ...
  A: 1) For the sake of discussion, let the charges be +3C and -5C. Then after the spheres are touched ...
Hydrogen fuel from PV5/20/2009
  Q: Hopefully this isn't too basic, but it seems so obvious to me. If you set up a Photo Voltaic cell, ...
  A: Your idea is technically feasible. Unfortunately it's not economically feasible -- at least not yet. ...
Rocket Help5/19/2009
  Q: I am in high school physics and we are working on a project by building rockets with an A8-3 engine. ...
  A: It's true that the acceleration will be given by F=ma. But understand that F must be the net force ...
electrcity(gauss theorem)5/18/2009
  Q: Consider a open hemisphere (i.e. it has open base).If a charge "q" is placed at any point on the ...
  A: Interpretation is a problem here. First think of a hollow closed sphere of some insulating material. ...
Impulse and Momentum5/17/2009
  Q: In a ballistics test, a 25 g bullet travelling horizontally at 1200m/s goes through a 30cm thick ...
  A: Let me start with the 2nd question. B) Momentum will be conserved. Momentum before = momentum after ...
anchor cable5/16/2009
  Q: A ship at anchor using sufficient chain anchor cable for the prevailing wind strength will surge ...
  A: Since the ship normally surges back and forth, the velocity normally changes from positive to ...
heat5/14/2009
  Q: At what temperature does the filament of electric bulb glows ?
  A: When a hot body is emitting energy in the form of light, the color of the light is tied to its ...
solving for theta 25/13/2009
  Q: The vitreous humor in the eye has a refractive index of n = 1.336. If the angle of incidence of a ...
  A: The equation is a statement of Snell's Law. See http://en.wikipedia.org/wiki/Refraction The ...
physics5/12/2009
  Q: Why it is easy to pull a suitcase instead of pushing it?I want this in equations.please send me ...
  A: I assume that whether you are pulling or pushing, the force is exerted at the same angle theta ...
mickey5/11/2009
  Q: The vitreous humor in the eye has a refractive index of n = 1.336. If the angle of incidence of a ...
  A: The light reaches the eyeball with an angle of incidence theta1. Theta1 is measured between the ...
Constructive interference condition.5/6/2009
  Q: A thin air gap of thickness d is present between two sheets of glass of thickness L. Suppose m is an ...
  A: You can discount a) because the interference is occurring because of the path length in the air gap, ...
physics5/2/2009
  Q: an elevator weighing 10,000N is supported by a steel cable. what is the tension in the cable when ...
  A: If the elevator car is accelerating up at 3 m/s^2, there is a net force acting on the car given by ...
physics5/1/2009
  Q: the rotating space station your standing in stimulates earths gravity when you are 500ft from its ...
  A: The simulated gravity has you standing so that if the station were a big soup can, you would be ...
optics - fisheye lens4/29/2009
  Q: "Is there a mechanical or post image process to reverse a fisheye lens view? I was interested in ...
  A: Yes, that can be done. See http://thesybersite.com/general/12mm-fisheye/index.htm Go down to section ...
egg lab4/28/2009
  Q: I'm suppose to hang a certain amount of mass from a spring and let it fall so that it only touches ...
  A: So that you know how I'm picturing this: You support the mass so the spring is at it's rest length ...
physics (motion/mechanics)4/27/2009
  Q: A car needs to generate in order to maintain a constant velocity of on a flat road. What is the ...
  A: There seems to be a couple gaps in your question. Let me guess at what you meant: A car needs to ...
Electricity4/24/2009
  Q: A common theme in science fiction is technologies or aliens which are able to nullify all use of ...
  A: Your question is hypothetical, so I started by letting my imagination go. Are permanent magnets ...
radar guns and electromagnetic properties4/22/2009
  Q: Some coworkers and I got into a discussion about radar guns (we're software engineers, so this isn't ...
  A: Yes, the radar gun's own velocity has a bearing on the reading it takes. Radar guns use the Doppler ...
Nozzle flow4/19/2009
  Q: I am solving a problem on nozzle flow..i was analysing the results..i am actually using a CFD ...
  A: This is a very complex topic. It's not something I learned about in my time on the Space Shuttle. I ...
Physics help4/18/2009
  Q: I am having trouble with a few study questions and would appreciate the help. 1.How much work is ...
  A: 1. Nothing is said about friction, so apparently we are to ignore it. By conservation of energy, the ...
Logic gate4/16/2009
  Q: Show that 1+1=6 logically
  A: Since you gave "Logic gate" as the subject, I assume we are talking about Boolean algebra. In ...
Electric Aircraft4/15/2009
  Q: I saw your answer about cost of running an electric car. How feasible is an electric commuter ...
  A: I don't know nearly as much about the power requirements of a plane as I do for a car. I searched ...
Blood Pressure4/14/2009
  Q: Does the blood pressure change at different heights like would it be different in the legs and the ...
  A: There is a test, called Ankle Brachial Pressure Index (ABPI), that compares systolic blood pressure ...
Physics-Index of Refraction4/13/2009
  Q: Hey, okay so i was doing an experiment that has to do with the index of refraction for different ...
  A: I did a yahoo search for ["index of refraction" "sea water"] and the first 10 hits included these 2 ...
Physics: vibrations and waves4/11/2009
  Q: I'm having problems rearranging a formula and was hoping you could help. The question has 4 parts: ...
  A: Yes, we have the relationship you gave to work with. And one other: 2*L = v/f where f is the ...
Frontal offset collision4/10/2009
  Q: Their is a frontal offset collision between a 2004 Pontiac grand am weighing 3640 lbs going at 43 ...
  A: Unfortunately your image didn't come through. The details about the location of the contact and the ...
friction4/7/2009
  Q: A 182 g block is launched by compressing a spring of constant k=200 N/m a distance of 15 cm. The ...
  A: I need to guess at something. Is the block launched to the left or right? I'll guess right. When ...
Is this possible at all??4/6/2009
  Q: A 900 yard par 3 is in South Africa. The green is shaped like the African continent and completely ...
  A: It's not possible without more information. Perhaps it expects you to make assumptions. Some ...
Temperature4/4/2009
  Q: 1)how can i relate the temperature of a body to kinectic energy? 2)what is the formula when ...
  A: 1) A short explanation of temperature (in kelvin) is that it's proportional to the average kinetic ...
The speed of a hit baseball4/3/2009
  Q: I have a question about a baseball thrown by a pitcher. If the batter has a constant hand and swing ...
  A: In addition to agreeing that the batter has a constant hand and swing speed, we also need to agree ...
Electrostatics4/1/2009
  Q: I have a question that is sort of hard to ask simply. But I hope my explanation will be sufficient. ...
  A: The table could have been neutral originally. But when the balloon and table touched, the balloon ...
Calculating electric force3/31/2009
  Q: Your Question calculating net electric force help needed right away? A small metal sphere (-2.10 x ...
  A: The force of attraction/repulsion between any 2 charges follows the relationship F = ...
buoy3/30/2009
  Q: i don't want you to answer my question. i only want you to recommend some refrences.it's not my ...
  A: Well I don't think you got the Steve that you intended. I'm Steve Johnson. But since it came to me, ...
Physics3/29/2009
  Q: 1. a .13 kg balll is swung vertically from a 0.50 m cord in uniform circular motion at speed of 2.4 ...
  A: 1. To keep it going in a circle, the net force acting on the ball must be a centripetal force, given ...
physics 12 Induction(flux)3/26/2009
  Q: a loop of wire of area .32m squared is placed in a .75 T megnetic field. the magnetic field is ...
  A: Faraday's Law says that emf = -d(Phi)/d(time) Phi is the symbol used for magnetic flux (I can't do ...
Magnetic field3/25/2009
  Q: Give an equation that represents the radius of curvature of an ion’s path as it passes through a ...
  A: Let the ion have mass m, charge q, and velocity v. And let the field strength be B. A force will be ...
Magnetic finding electrostatic force3/24/2009
  Q: Can anyone help me with Numerical Response 6 and question 19 on this website ( questions are on ...
  A: 6. This problem needs the answer you chose for velocity in question #18. I'll call that V18. Since ...
physics3/23/2009
  Q: An automobile initially moving at 72 km/hr jams the brakes and skids to a stop in a distance of 24 ...
  A: The original kinetic energy is given by KE = (1/2)*m*v*2 First convert the km/hr to m/s: 72 km/hr * ...
buoy3/22/2009
  Q: i want to know about total forces on a floating structure or buoy.i want to calculate these forces ...
  A: That would be very much related to the shape of the structure or buoy. First consider a boat at ...
Force at x direction3/21/2009
  Q: 1 i have one question.If one block have a force from Up,Fy=200N and at side left and right it have ...
  A: I'm not sure if I'm interpreting your question the way you mean it. It seems like there are forces ...
electric force3/20/2009
  Q: Two charged objects of identical size and mass are brought together in brief contact. If the one ...
  A: When they are brought into contact, the 1.70uC will neutralize -1.70uC from the mass with -2.50uC ...
Question3/19/2009
  Q: On an amusement park ride, passenger are seated in a horizontal circle of radius 7.5m. The seats ...
  A: Angular acceleration can be calculated (in this case) using this equation Wf = Wo + alpha*t where ...
electric force3/18/2009
  Q: If the electric field strength between 2 charged particles that are 1.55m apart is 2.70 x 10^-4 N, ...
  A: Electric field strength is measured in volts/meter. You gave units of Newtons for the first case and ...
electric field3/17/2009
  Q: "Hi, A 2.5uC charge is placed 10.0 cm from a 7.0uC charge. At what point between the 2 charges ...
  A: Net electric field is a vector sum. You individually consider the field from each individual charge ...
electric potential3/16/2009
  Q: an investigation is performed using a apparatus. Electrons are accelerated from rest from the ...
  A: 1) The electrons are given kinetic energy. Consider a single electron. KE given to one electron is ...
electrostatic force3/14/2009
  Q: Can you please show me how to do questions 13 and Numerical Response 7 on this site: ...
  A: 13. If q1 were the only other charge in q2's neighborhood, q2 would experience a force F1. If q3 ...
Physics3/13/2009
  Q: A 0.175-kg coffee cup is placed on a merry-go-round with uS=.70, 3m from the center of rotation. The ...
  A: We need to convert the given rotational speed to units of radians/second. Then we generally call it ...
Spin applied to a ce ball3/12/2009
  Q: When striking a cue ball slightly to the left of center which direction does it spin? I've been told ...
  A: A more common spin put on a cue ball is backspin. Make a sketch from the viewpoint as if your ...
Gaussian surface3/11/2009
  Q: .as a follow up: 1) What is a Gaussian surface 2) What difference wiuld it make if I had a charge ...
  A: 1) A Gaussian surface is a closed hypothetical surface. I indicated in the previous answer that the ...
surface wave propagation in real life3/10/2009
  Q: In real life, when a solid material (such as a piece of wood or plastic - not perfectly isotropic ...
  A: Please understand, I don't have any study or experience to support my intuitive reaction to your ...
electric field3/9/2009
  Q: sir few questions related to electric field 1) Why no field can exist inside a conductor? or why ...
  A: 1) If a chunk of conductor is placed in an existing electric field, the mobile charges in the ...
Gauss Law3/8/2009
  Q: Why is the electric field inside a conducting shell zero and how is this a consequence of Gauss law? ...
  A: One more assumption that is required is that there be no charges placed inside the shell (such as on ...
help plz3/6/2009
  Q: I’ve some questions Can u help me with them please? Q1. One car travels due east at 40Km/h, and ...
  A: Q1. If you had asked if the speeds were equal, I would say yes. But velocity is a vector so the ...
Physics3/5/2009
  Q: 1. A stone is thrown horizontally at a speed of 5.0 m/s from the top of a cliff that is 78.4 m high. ...
  A: 1a. The time for the stone to reach the bottom of the cliff is the same as if it were merely dropped ...
motion3/3/2009
  Q: i've several Qs can u help me plz!! Q1. A horse canters away from its trainer in a straight line, ...
  A: 1a. During the canter, it goes 116 m, during the gallop, it goes 58 m -- total distance 116+58 ...
physics3/2/2009
  Q: if there is no friction how much time the body will take to come to rest?
  A: If the moving body is going vertically up, it will stop briefly when all of its kinetic energy has ...
The LHC3/1/2009
  Q: Greetings, I am endeavoring in a research project on the Large Hadron Collider. I have succeed in ...
  A: For Pros, I would simply say discovery, knowledge and understanding. You say you have learned the ...
collision2/28/2009
  Q: How are you? I am in a car moving at constant speed towards another similar car (in every aspect).I ...
  A: I'm doing well, thanks -- hope you aren't hurt in the collision. No. Newton's 3rd says that the 2 ...
SHM2/26/2009
  Q: sir i am unable to get the answer for the following numericals. Can you explain how to solve them. ...
  A: 1) My initial interpretation of the problem was that a single hydrogen atom has a bond with material ...
Physics (Friction and Forces)2/25/2009
  Q: Book: physics Principles and problems 17. A girl exerts a 36 N horizontal force as she pulls a 52 N ...
  A: 17. The coefficient of kinetic friction has this relationship between force of friction and the ...
rotational motion and the law of gravity2/24/2009
  Q: a car traveling at 30.0m/s undergoes a constant negative acceleration of magnitude of 2.00m/s^2 when ...
  A: This kinematic equation will give you the distance traveled: Vf^2 = Vo^2 + 2*a*s where Vf is final ...
What is the most effective way to produce AC from a (DC) battery (-ies) ?2/23/2009
  Q: I must thank you for your recent answer, it was useful ! I want to make an analysis about an ...
  A: The site http://en.wikipedia.org/wiki/Crystal_oscillator indicates that "Quartz timing crystals are ...
Ideal gas n thermodynamic2/22/2009
  Q: The specific latent heat of vaporisation of steam is 2.26MJKg^-1.When 50cm^3 of water is boiled at ...
  A: a) Converting the volume of liquid water to m^3: 50 cm^3 = 50*(10^-6 m^3) = 5.0*10^-5 m^3 Using the ...
friction2/21/2009
  Q: Why does frictional force increase when surfaces in contact are polished beyond a certain extent? ...
  A: That's interesting. I suspect, but I might be wrong -- again, that both have to be the same metal or ...
Physics2/20/2009
  Q: Find the ampliture, frequency and period of an object vibrating at the end of a spring, if the ...
  A: The equation you gave is a standard way to describe an oscillation. It is more often a sine function ...
friction2/19/2009
  Q: Why does frictional force increase when surfaces in contact are polished beyond a certain extent?
  A: I learned as a kid that my mother's freshly waxed floors were slippery. Walking on them wearing ...
I'm a physics student who has to do a experiment on trash and its effects on student life.2/17/2009
  Q: I'm not sure if you ever herd of group iv but basically its a huge experimentation with all of the ...
  A: Hmm -- trash, Physics and the effects on students' lives. First, what can we see about the ...
Hammer Rotation Puzzler.???2/16/2009
  Q: .. Below is a link that shows a blond Russian lady Hammer thrower (ther are about 4 other ...
  A: You indicated in some of the versions of your question that you would tell us what you thought the ...
Abour Uniform Circular Motion2/15/2009
  Q: A mass of 0.5Kg is whirled at 120 rpm in a horizontal circle at the end of a string 2 meters long. ...
  A: a) Angular velocity is expected to be in units of radians per second. You have rotational velocity ...
The Best Magnetic core material2/14/2009
  Q: We want to build for a science fair project a pulsed electromagnet. The pulse from an accumulator or ...
  A: I regret that design of magnetic devices was not something my career gave me any experience in. So I ...
vectors problem2/13/2009
  Q: I was having a bit of trouble with a homework problem and was wondering if you could help in ...
  A: Just to be sure you can draw this: Island 1 is at the origin of an x-y (or EastWest-NorthSouth) ...
Circular Motion2/12/2009
  Q: In recent years, a number of nearby stars have been found to possess planets. Suppose, the orbital ...
  A: A body in motion tends to continue with no change in its velocity vector, meaning it tends to move ...
Hammer Rotation Puzzler.???2/11/2009
  Q: .. Below is a link that shows a blond Russian lady Hammer thrower (ther are about 4 other ...
  A: The thrower is the center of the rotation during the throw. As it's flying on its own, the handle ...
impact load on an IC2/10/2009
  Q: I want to use a device rated at up to 8g. will it withstand a 500KG impact , I don't know the ...
  A: I really need more information. My first reaction was to say that 500 kilograms is 500,000 grams, a ...
average weight on scales?2/7/2009
  Q: If a person weighing 100 lbs. started juggling three balls weighing 5 pounds each, stepped on ...
  A: This is an interesting question! Clearly if the person just stood there holding one of the balls, ...
physics2/5/2009
  Q: how can objects move with constant velocity even when an appiled force acts on them because the ...
  A: I could say that you answered your own question. If I break what you wrote in 2 pieces, the second ...
Motion2/4/2009
  Q: 1. When do you consider an object to be moving? 2. How is the change in position of an object ...
  A: 1. That's actually hard to define easily because most of the words I want to use mean about the same ...
elecetrostatics1/30/2009
  Q: Differentiate between electric potential and electric potential energy at a point in an electric ...
  A: Electric potential: The phrase electric potential is used in this sense: "The electric potential ...
STATIC COEFFICIENT1/28/2009
  Q: STEVE, i HAVE A PROBLEM THAT ASKS FOR THE STATIC COEFFICIENT GIVEN ONLY THAT I HAVE A BOX THAT ...
  A: Just to be sure: I'll assume the 18 degrees is measured from horizontal. And I will assume they ...
eLectrics1/27/2009
  Q: A small plastic ball of mass 6.90 multiplied by 10-3 kg and charge +0.150 µC is suspended from an ...
  A: Please allow me to show you how to make exponents here. Use the "^". (shift+6) So it would look like ...
linear motion1/26/2009
  Q: What is the impact speed when a car moving at 100km/h bumps into the rear of another car traveling ...
  A: If you were in the slower car, watching the faster car coming toward you (and if you could ignore ...
Power Grids1/25/2009
  Q: The following video shows a substation cutting the power: http://uk.youtube.com/watch?v=hIkNY5xjy5k ...
  A: Inductors store energy. When there is current flowing through an inductor, it stores energy and uses ...
Micrometeorites and the Moon1/23/2009
  Q: Steve, I am stuck on this question. Can you help point me in the right direction? If one ...
  A: One micrometeorite will consume the same space as a cube with the dimensions of the diameter of the ...
reversible process1/21/2009
  Q: sir i know this is out of your subject expertise but since whenever i have asked any question to u i ...
  A: Of all classical physics, this is perhaps the most difficult concept to accept as logical, in my ...
Physics: balancing torques1/20/2009
  Q: I'm having trouble with all the different weights. I would appreciate help with this problem: A ...
  A: You can arrange just about any combination of weights for balance by placing them in the right ...
reversible process1/19/2009
  Q: sir i know this is out of your subject expertise but since whenever i have asked any question to u i ...
  A: I'm happy I've satisfied you in the past. Let's see how this turns out. I reviewed my old college ...
physics1/18/2009
  Q: How high will a body rise that is projected vertically upward with a speed of 100ft/s? How long will ...
  A: I expect you have been given a set of 4 kinematic formulas. To choose the one that will work on your ...
Gravitation1/16/2009
  Q: How will you draw the graph of Kepler's Third Law- i.e. Square of Time Period proportional to Cube ...
  A: I did a yahoo search for ["Kepler's Third Law" graph] and got sites with different ways of plotting ...
Physics1/15/2009
  Q: What is the positive and negative charges in physics langauge?Please tell me 5 positive points and 5 ...
  A: There really is no significant meaning to the names given to the 2 electrostatic charges. It's ...
law in physics1/14/2009
  Q: I was wondering what the law in physics means that for every action there is an equal and opposite ...
  A: Newton's 3rd Law refers to actions of 2 bodies on each other. If body A exerts a force on body B, ...
velocity1/13/2009
  Q: how do you find the maximum velocity of water shot from a water gun? At what point does the squit ...
  A: If you're shooting your squirt gun out a window at someone below you, that complicates things (the ...
Gravity Machine1/12/2009
  Q: Is there a machine that can multiply gravity? Or is it possible to build one?
  A: If such a thing does exist, it's a big secret. I very much doubt it. On your 2nd question, I know ...
electronics1/10/2009
  Q: how will i make a generator out of aluminum foil and without using any magnet?
  A: Unfortunately I don't know what you wish to generate. I did a search for {"aluminum foil" generator] ...
Physics1/7/2009
  Q: You can obtain a rough estimate of the size of a molecule by the following simple experiment. Let a ...
  A: First, I'm on mission to teach people how to do exponents on a site like this. Use the caret, ^ ...
time dilation1/6/2009
  Q: does the dilation mean that time really passes more slowly in moving system or that it only seems to ...
  A: I said in my profile that I decline questions on relativity and Atomic Physics. But I think I can ...
Potential and Internal Energy1/5/2009
  Q: When doing an experiment, if you set up a an aluminum cylinder with a weighted bucket on one side ...
  A: I'm trying to develop a picture in my mind. I have an aluminum cylinder, laying on a table with its ...
Physics1/2/2009
  Q: A 5.3 kg bucket of water is raised from a well by a rope. If the upward acceleration of the bucket ...
  A: I imagine you know Newton's 2nd Law. The equation F=m*a is a common way to express it. Using that ...
9th grade physics1/1/2009
  Q: If the optimal angle is 45 degrees for achieving the maximum distance when shooting a canon ball in ...
  A: With experiments, it's important to control the consistency of the things you don't want to change ...
physics12/31/2008
  Q: A 9.0 kg present (which you hope is your new gaming system) sits on your rough, level carpet. YOu ...
  A: If it requires 61 N, applied horizontally, to slide it horizontally, then the force of static ...
Physics12/30/2008
  Q: salini filled water in a plastic bottle. she then made a hloe on the bottom of it. water came out ...
  A: E.S, I'll assume the bottle has a tight cap. Now, a review the sequence of events: When the bottle ...
how much force12/28/2008
  Q: a speaker is set up on a stand that weighs about 55lbs. how much force does it take to move the ...
  A: I need to make some assumptions about the problem: a speaker, and its stand, weigh about 55lbs and ...
optics12/27/2008
  Q: How does the temperature of sugar (eg. glucose or fructose) solutions affect the angle at which it ...
  A: I'm sorry, I didn't even know about this phenomenon of rotation of polarised light. I found some web ...
Potential and kinetic energy/Springs12/26/2008
  Q: This question was on my final for mechanics. A 5 kg block rests on a frictionless hill attached to a ...
  A: I think there are some missing details. I can't tell how or if the 2 blocks are connected to each ...
electromagnetic field12/23/2008
  Q: Can you tell me please, why a neon tube traversed by an electric current doesn't attract ...
  A: If you increase the current, you will increase the strength of the magnetic field. There's a direct ...
electromagnetic field12/21/2008
  Q: Can you tell me please, why a neon tube traversed by an electric current doesn't attract ...
  A: Remember that the lines of magnetic induction for a long straight wire, carrying current i, are ...
Residential Electrical Circuits12/18/2008
  Q: Mr. Johnson: I have seen interesting information about 'dirty' electricity on the Graham-Stetzer, ...
  A: Instead of dirt, I use the term noise. Electro-magnetic interference (EMI) is the technical term. ...
rotational mechanics12/16/2008
  Q: How can one predict which hemisphere of earth we are in by looking at the direction of rotation of ...
  A: Many people believe that "all basins" in the northern hemisphere rotate one way and the other in the ...
Force distance in air12/13/2008
  Q: This is a 9/11 towers physics question. I am trying to remember my physics and was wondering if you ...
  A: This tragedy has been analyzed by people who had access to details of the towers. Even with the ...
resonance12/10/2008
  Q: sir this is regarding resonance if you can refer the following site page 8 and 9 on forced vibration ...
  A: OK, I can see what's behind your question. You're saying "I see what the math says, but it doesn't ...
Newtonian Kinematics12/8/2008
  Q: I have a few questions; however they are similar and perhaps even maybe have the same answer. What ...
  A: 4 equation linear kinematics model? I use equations that assume that original or final displacement ...
electrostatics12/7/2008
  Q: what is meant by electrostatics & is it really that the charges didnt move
  A: When you rub a glass rod with silk, the glass rod becomes positively charged and the silk becomes ...
Fluid/presure12/5/2008
  Q: Hey, MR.Steve, i need you help on this question. Please take a look at it The drawing shows a ...
  A: The weight of the rock is the force, Fo, applied to the system at the output plunger. This causes ...
Fluids Help12/4/2008
  Q: Hey Sir, I got a question on fluids. Could you please look into it and help me. Thanks a lot! ...
  A: The area of the roof is 3.7 x 4.5 m^2. The pressure that will just equal the maximum the roof can ...
kinetic energy..12/2/2008
  Q: i was wondering if u can help me with these questions 1) In pool, when the cue ball hits another ...
  A: 1) In pool, there is a complication in that spin can be put on the ball. Spin affects the behavior ...
conductors11/29/2008
  Q: if a charge is placed inside a hollow spherical conductor, not at the center, how will be the ...
  A: This is going to be hard to describe and probably hard for you to picture. Draw a cross section of ...
surface tension11/27/2008
  Q: sir why do we see two meniscus in liquid inside glass tube? Lower meniscus and upper meniscus. I ...
  A: Surface tension, cohesive force and adhesive force don't agree on the preferred shape of a meniscus. ...
Egg drop- energy conservation11/25/2008
  Q: how would you explain energy conservation in an egg drop (with no parachutes, foam, cotton balls, ...
  A: From the height that egg starts at, it has gravitational potential energy. This energy will be ...
Fluids/Pressure11/21/2008
  Q: Hey Sir, I need help on this question. I hope you please take a look at this and explain to me how ...
  A: I found 2 sources http://hypertextbook.com/facts/1999/KatrinaJones.shtml and ...
project on friction11/19/2008
  Q: I want to design a machine which can climb up or down over a rope with friction only without help of ...
  A: A few more details would have helped me. I'll list a few general thoughts but also list some of the ...
Parallel Circuits and light bulbs11/18/2008
  Q: I have so far learned that theoretically, light bulbs connected in parallel circuits have the same ...
  A: If theory was not followed, some assumption made in the statement of the theory must have been ...
aero foil11/17/2008
  Q: ) Aerofoils are designed to speed up air flow on the upper section thus prodicing lift.How then can ...
  A: In addition to lift due to the wing shape, lift is produced by the angle of the airfoil. Imagine a ...
Force and acceleration11/15/2008
  Q: When taking off, fully loaded the mass of the plane is 2560kg.The two jet engines can exert a total ...
  A: 1. Newton's 2nd Law says that mass m undergoes acceleration a when a net force Fn is exerted on it ...
semiconductors11/14/2008
  Q: can u clearly figure out whats going on in p-n junction and please give me a detailed information ...
  A: I have found several websites for you that will do a better job of explaining than I could. Please ...
velocity of a softball11/13/2008
  Q: Mr Johnson, In my physics class we are doing a project on the physics of sports, and i chose the ...
  A: In this question I think we need to ignore any speed given by a flick of the wrist or forearm. So ...
Gravitation and Newton's Synthesis11/11/2008
  Q: The Sun's gravitational pull on the Earth is much larger than the Moon's. Yet the Moon's is mainly ...
  A: As the Earth rotates on its axis each day, the distance from the Moon to water molecules near the ...
Physics problem Force and Acceleration11/10/2008
  Q: Claudia stubs her toe on the coffee table with a force of 100 N. Ignoring any frictional effects, ...
  A: a) If Claudia's toe exerts 100 N on the table, by Newton's 3rd, the table exerts 100 N on her foot. ...
Conservation of Energy11/9/2008
  Q: A skier of mass m starts from rest at top of a solid sphere of radius r and slides down its ...
  A: a) According to Conservation of Energy, the skier's velocity will be given by v in the equation ...
viscosity11/8/2008
  Q: sir few questions on viscosity i all books i have read it is written that if we consider a real ...
  A: 1) It is said that the fluid is flowing -- we don't know why, but there is a flow. The bottom layer ...
physics: work and energy11/5/2008
  Q: I have two questions with which I am struggling: 1. a car is traveling horizontally at 4 m/s after ...
  A: You could do both of these with kinematic equations. But I appreciate you gave "work and energy" as ...
gravity11/4/2008
  Q: A particular race car can cover a quarter mile track (402 m) in 6.20 s starting from a standstill. ...
  A: Newton's Law of Universal Gravitation says the force of attraction between any 2 bodies is F = ...
Physics and tension11/3/2008
  Q: Okay i'm stuck on this. you have three blocks connected by a massless string sitting on a ...
  A: You are right about the acceleration, 3 m/s^2 for all 3 blocks. To understand how to calculate ...
Understanding Forces11/2/2008
  Q: I'm currently taking Honors Physics in Highschool and I'm still unclear on how to approach a problem ...
  A: To avoid the broom rotating, I will assume the 5.0 N force is directed along the shaft (as opposed ...
bernoulli's theorem11/1/2008
  Q: sir i am trying to understand bernoulli's theorem where the proof is given based on energy ...
  A: 1) >what is meant by pressure energy in flowing fluids? That term is new to me but I think I know ...
mechanics10/31/2008
  Q: A Fotballer is set to kick a critical free-kick 11m from the goal during a critical match.If the ...
  A: I can't give a definite numerical answer for either maximum or minimum. a) Maximum momentum ... I ...
logic10/30/2008
  Q: A man is trapped in a room. The room has only two possible exits: two doors. Through the first door ...
  A: Three ideas that I have come up with: 1. There doesn't seem to be anything threatening about the ...
braking or tuning better?10/29/2008
  Q: a car is approaching a wall at V m/s velocity, is it better to turn the car keeping the velocity ...
  A: I will assume this is a very long wall so the car can't just do a small zig-zag and miss the ...
Momentum10/28/2008
  Q: Hey Mr. Johnson, I actually two questions in which I seriously need help. It would be great if you ...
  A: 1. The concept is momentum before = momentum after. And momentum is m*v, mass times velocity. (In ...
Projectile motion10/27/2008
  Q: An airplane is heading due south at a speed of 600 km/h. If a wind begins blowing from the southwest ...
  A: This problem isn't about projectile motion. Projectile motion involves something projected generally ...
help with physics problem10/26/2008
  Q: I was hoping maybe you could help me with an extra credit problem. I cant figure it out. ...
  A: I'm going to display the 4 kinematic formulas with my version of variable names and number them so I ...
magnetic permability10/25/2008
  Q: I am stuck with a concept in physics. I am using the magnetic permabililty of air in an equation but ...
  A: Notice in the table in the website http://en.wikipedia.org/wiki/Permeability_(electromagnetism) ...
science project10/24/2008
  Q: My 6th grader is doing a science project on "Can seawater be desalted by freezing. What experiment ...
  A: It turns out that the answer is yes. I didn't know, so I did some searching which didn't didn't find ...
physics question10/23/2008
  Q: The space shuttle is in a 190 mile high orbit. What are the shuttle's orbital period, in minutes, ...
  A: You can solve this using equations 4.1 thru 4.5 in Section 4, The Appendix, of this site: ...
question10/21/2008
  Q: I have a question from my homework: There are to blocks A and B. The mass of A is 20kg and the mass ...
  A: I assume the blocks are separated on the floor by a distance so that when the pulley lifts, the ...
Projectile Motion10/19/2008
  Q: When Babe Ruth hit a homer over the 7.5m high right field fence 95m away from home plate, roughly ...
  A: Let the original velocity you need to find be called Vo. It has horizontal and vertical components. ...
Physica10/18/2008
  Q: A soccer ball is kicked down the field in three trajectories (each reaches same height but first ...
  A: Since each goes equally high, each will have equal time in the air. You can treat the vertical ...
rotation!!!!10/16/2008
  Q: i`m very much confused in rotation,momemt of inertia & torque. please help!!
  A: Let's picture 2 objects that you could call wheels. One of them is a disk made of wood and the other ...
HT 132 KV10/15/2008
  Q: I have a weighbridge installation having load cells (Transducers), 1 132 KV high tension passes over ...
  A: I wonder if I misinterpreted your original question. I thought the 132 KV line was interfering with ...
Physics10/14/2008
  Q: The velocity of 1.50 kg block sliding down a frictionless inclined plane is found to be 1.36 m/s. ...
  A: Using the original & final speeds and time, use the equation Vf = Vo + a*t to find the acceleration, ...
Physics10/12/2008
  Q: All force need not make bodies move. Will impulse be zero, even if the force is not zero? Could you ...
  A: E.S, >>All force need not make bodies move. That is true. That would be a case where the vector ...
HT 132 KV10/11/2008
  Q: I have a weighbridge installation having load cells (Transducers), 1 132 KV high tension passes over ...
  A: I would expect the technical support department of the companies that supplied your load cell and/or ...
newtons law10/10/2008
  Q: A person jumps from the roof of a house 4.8 m high. When he strikes the ground below, he bends his ...
  A: You say that you are asked for downward velocity. At the moment of contact with the ground? Or maybe ...
newton's law10/9/2008
  Q: A particular race car can cover a quarter mile track (402 m) in 6.20 s starting from a standstill. ...
  A: The symbol g stands for the acceleration due to gravity. The value is 9.81 m/s^2. This is the ...
Hazards of 400 nm lasers?10/8/2008
  Q: What hazards -- other than thermal burns -- does a 400-nanometer-wavelength continuous [i.e. ...
  A: You are right about 400 nm being the longest wavelength classified as "black light". That is the ...
Electric Field and Application10/7/2008
  Q: What is the importance/relevance to know the electric field distribution of a electrical apparatus? ...
  A: If a signal cable passes through an area with a high amplitude AC electric field, it could introduce ...
force calulation10/5/2008
  Q: i am trying to find out the equivalent mass to 50nm of force. this if applied vertically. ie what ...
  A: The abbreviation nm stands for Newton-meters, a unit of torque. See this useful website ...
Career question10/4/2008
  Q: Hey I was looking at your experience information, and the areas in physics you mentioned, such as ...
  A: Interesting connection. Enjoy homecoming. I grew up in Moorhead and attended Kindergarten at what ...
Boiling of water10/3/2008
  Q: My question involves the mechanism of water boiling. My understanding of what is happening is that ...
  A: You have the right idea about temperature. And perhaps just referring to kinetic energy is enough ...
Magnet motion/rotation10/2/2008
  Q: I have an invention that I’m putting on hold till I can figure out the physics of the concept will ...
  A: I need to ask a couple questions about the experiment. 1. I'm not getting the picture of the ...
Physics10/1/2008
  Q: A model rocket is fired vertically from rest. It has a net acceleration of 17.5m/s^2. After 1.8s, ...
  A: During the powered phase of the flight Vf = Vo + a*t where Vf is final velocity, Vo is original ...
Newton's Laws of motion9/29/2008
  Q: I would like to seek your guidance on the following problem with respect to the concept of inertial ...
  A: One of the equations used when studying one dimensional motion is y = Vo*t + (1/2)*a*t^2 where y is ...
Kinematics of motion in a straight line-mechanics9/28/2008
  Q: Cn u plz gv explaination 2 d solutions bit by bit in brief?Cz i actually cnt wrk out hw 2 use d ...
  A: We can say now that the average speed, Vave = D / 6*T It's going to be important to keep track of ...
Mechanics-newton's law of motion-phy9/26/2008
  Q: Cn u xplain the solutions steps by steps?Cz i really dnt understand wen i revise it nw.Tnxs. A ...
  A: i) Friction is given by Ff = mu*N where mu is 0.2 and N is the force of the basket exerted normal to ...
projectile motion9/25/2008
  Q: An arrow is shot into the air at an angle of 61.8 degrees above the horizontal with a speed of 21.4 ...
  A: The initial y component of velocity is Vyi = Vi*sin61.8 Then you can use the general equation Vf = ...
gravitation9/24/2008
  Q: helo 1) why is the gravitational potential enrergy of a body of mass m at any given height R from ...
  A: 1) My Physics book says that "Convenience usually determines that the potential energy is taken as ...
Physics tension9/23/2008
  Q: An elevator cable may break during acceleration when lifting a lighter load than it normally ...
  A: Case 1: When the elevator is at rest, or at a constant velocity, the car is not accelerating. That's ...
net external forces9/22/2008
  Q: Which of the following can NOT be a consequence of a net external force acting on an object? (A) ...
  A: A If an object experiences acceleration, a net external force must be acting on it: Force is related ...
help with physics problem9/21/2008
  Q: I was hoping maybe you could help me with an extra credit problem. I cant figure it out. ...
  A: Ralph's ground speed will be reduced by the wind speed: vr = 25 - 8.4 = 16.6 mi/hr Ralph's time, ...
help with physics problem9/20/2008
  Q: I was hoping maybe you could help me with an extra credit problem. I cant figure it out.
  A: The image you posted seems to be a study guide or notes. I don't see a problem to be worked. I do ...
physics9/19/2008
  Q: A skier is gliding along at 4.0 m/s on horizontal, frictionless snow. He suddenly starts down a 16° ...
  A: a) The component of acceleration due to gravity pointed down the slope, ad, will be g*sin16. Use the ...
terminal voltage9/17/2008
  Q: Why does terminal voltage decreases when more current is drawn from the cell? In my book of class ...
  A: In order to increase the current drawn from a particular cell, the resistance of the external ...
physics,9/16/2008
  Q: Pr. Electromagnetic waves travel at the speed of light and carry energy. Energy is equal to ...
  A: Let's say my favorite radio station broadcasts at 94.3 MHz. Planck's constant is h = 6.625 * 10^-34 ...
electrophysics9/15/2008
  Q: this question was in my mid final exam this year. does an increase in the frequency of sampling rate ...
  A: a) Time resolution is indeed increased. If the sample frequency were 100 Hz, you would get 1 sample ...
gravitation9/14/2008
  Q: 1) The newton's law of gravitation is strictly accurate for point masses. But if the bodies are of ...
  A: 1) >what does the above statement mean? That only means that they have to be far enough apart that ...
centre of mass9/13/2008
  Q: sir i wanted to ask 1) when a disc is rolling on a plane surface or on an inclined plane , it has ...
  A: 1) The mass of a body can be represented as being concentrated at the calculated c.o.m. for many ...
physics9/12/2008
  Q: what are the effects of earth's rotation on gravitational force?
  A: A pebble sitting on the surface of the earth is moving in a circle as the earth rotates on its axis. ...
current9/11/2008
  Q: I am puzzled over the meaning of “drawing current.” Please tell me if the following is correct. ...
  A: >the current flowing through (1) the wires and (2) the motor is the same, and is determined by ...
electrostatics9/10/2008
  Q: wat is capacity of spherical capacitor internally grounded.thorough answer
  A: Capacitance is given by the equation C = q/V You might say capacitance is a measure of how much the ...
"Investigatory Projects"9/6/2008
  Q: Mr. Steve Johnson, I'm a highschool student and I'm really here to ask you about ...
  A: I need to ask you some questions: Are you just starting to study Physics? How major a project is ...
strong nuclear force9/3/2008
  Q: is that the bond due to strong nuclear force is greater between neutron-neutrons and neutron-proton ...
  A: I said in my profile that I decline questions on relativity and Atomic Physics. I'm a high school ...
I want to ask you 3 question8/27/2008
  Q: 1.When we look at a apple? do we really "SEE" the apple with our eye? ...
  A: 1. "do we really "SEE" the apple with our eye?" The definition of the word "see" has been configured ...
Sciintillation8/26/2008
  Q: This is a follow on to my previous question. 1) are there common household products (man is this a ...
  A: Most of what I am able to do for you is give you links to material related to your interests. You ...
mass8/24/2008
  Q: i read that mass is a constent, if it is, than how could it increase with special relitivity?
  A: When it is said that mass is a constant, an approximation is being used. This approximation is ...
rotational motion8/22/2008
  Q: sir few questions 1) what is the difference between circular motion and rotational motion? all ...
  A: 1) Those terms, plus revolution, can be a can of worms. My 2 dictionaries indicate that the ...
physics8/21/2008
  Q: A girl is playing tennis against a wall. She hits hte tennis ball from a height of 0.5m above the ...
  A: Different approaches work for different people. I prefer to reason it out. See this answer of a ...
electric motor circuit8/20/2008
  Q: My question concerns a 12v DC motor driving a cooling fan in a car. If there is a high resistance ...
  A: When resistance develops in the line carrying power to a load, like your fan, the current does ...
audio and physics8/19/2008
  Q: I am trying to figure out how to apply work and pressure formulas to an amplifier and speaker system ...
  A: Unfortunately I'm not really up on this topic. I did some searching and found some info that helps ...
Doppler effect8/17/2008
  Q: What is the Doppler effect?
  A: The Doppler effect is the name given to a phenomenon that movies and TV often include as sound ...
thermodynamic8/16/2008
  Q: why heat is zero in aconstant heat material
  A: If a body's temperature is not increasing or decreasing, that means it is not loosing or gaining ...
rotational motion8/12/2008
  Q: after so long i could find you available as you were always maxed out. I wanted to ask so many ...
  A: 1) Interesting question. I don't think I ever had a feeling for what physics meant by that. ...
gravitation8/11/2008
  Q: what will be the change in weight of a body if earth start spinning faster or stop spinning and if ...
  A: So much detail you couldn't find the answer you wanted? Repeating: If the earth stopped spinning, a ...
gravitation8/9/2008
  Q: what will be the change in weight of a body if earth start spinning faster or stop spinning and if ...
  A: An object sitting on the surface of a spinning body -- like the earth, requires centripetal force ...
Physics8/7/2008
  Q: What is the formula of Displacement due to gravity?
  A: An object in free fall due to gravity (assuming no air drag) increases it's y displacement, over a ...
physics8/6/2008
  Q: what is the angle between the two forces of equal magnitude when their resultant is also equal to ...
  A: I'll show you 2 ways to work that out. 1) Think of the graphical method where you draw both ...
Electrostatics8/4/2008
  Q: I have a question about concepts for you. When I study the electrostatics,there is two concepts ...
  A: My use of gravity was intended to show that encountering a force that is at some angle to existing ...
please help me to answer this problem.8/3/2008
  Q: 27.0) 1.5 kg of gas expands in a closed system from 6.5 kPa and 50L to 100L. Determine the work done ...
  A: I'm going to explain the concept, the work you need to do, and get you started on all 4. The work ...
Electrostatics7/30/2008
  Q: I have a question about concepts for you. When I study the electrostatics,there is two concepts ...
  A: I agree with concept #1 (except that it doesn't say that the point charge is positive -- that's an ...
electricity7/29/2008
  Q: Its me again:)Just read from a text book " Once we thought that electricity travels at the speed of ...
  A: My followup is at the bottom. OK, found the page that claims current is faster than light. I have a ...
Exhaust from the rockets7/28/2008
  Q: does the smoke/exhaust from rockets remain as such in the space? or gets dissolved?. because when ...
  A: Most of the exhaust is expelled before the ship has reached orbit. For example the Shuttle's Main ...
Coefficient of Restitution7/25/2008
  Q: How does the Height of Drop affect the COR of a bouncing ball? Does it simply increase as the ...
  A: Ahhh, the difficulties in getting experimental data to agree with the principles. I have several ...
converting radio signals7/24/2008
  Q: I have heard about converting radio signals into optical signals and i was wondering if you could ...
  A: This technology, called Radio over Fibre or RoF, is used when a signal that is intended to be ...
Coefficient of Restitution7/23/2008
  Q: How does the Height of Drop affect the COR of a bouncing ball? Does it simply increase as the ...
  A: As the height of drop, H, increases, the height of the rebound, h, increases. The relationship ...
Waves7/22/2008
  Q: I don't remember the right way to look at this problem. I wave two waves sin(x) and cos(3x) adding ...
  A: Imagine that you placed a microphone at a random point between 2 speakers, and played a pure ...
air blast7/21/2008
  Q: what is a air blast reject. 2. how to find torque in a conveyor.
  A: It would have helped if you had explained the situations of these questions a bit. My answer is ...
friction7/20/2008
  Q: sir i have few questions related to friction 1) I read in my book that extremely smooth surface ...
  A: 1) Friction is a complex subject. The coefficient of friction for any 2 surfaces must be measured. ...
electricity7/19/2008
  Q: Its me again:)Just read from a text book " Once we thought that electricity travels at the speed of ...
  A: That electricity can travel travel faster than the speed of light was news to me. I did some ...
gravity7/18/2008
  Q: imagine two equal plane one of them is on earth and the other one is on mars which of them needs ...
  A: Gravity on Mars is less than here. To figure the ratio: Acceleration due to gravity: Earth 9.8 ...
electricity&magnetism7/17/2008
  Q: sir, imagine a situation when we are standing in an elevator,a uniform magnetic field is existing ...
  A: Whether or not a magnetic field would cause a force to be exerted on an electron depends on whether ...
Transference of energy7/15/2008
  Q: I was wondering if you could help me. Can you tell me how fast my car (weighing 1192 Kg)would have ...
  A: Let me explain why it's difficult to answer. For your car to come to a stop, it needs to decelerate ...
magnet7/14/2008
  Q: I have a long series of questions related to magnetic fields and I would like to find the answers on ...
  A: I have seen good sites with physics lessons online, unfortunately I haven't recorded the url of any ...
What physics calculation(s) would be used in this scenario?7/13/2008
  Q: I'm not trying to figure out an actual problem. I'm trying to figure out the proper formula(s) that ...
  A: So I guess the object is going to pull the tree down on top of itself. Or perhaps the object hits ...
induction motors as generators7/11/2008
  Q: I am currently working on low speed wind mills. I have read a great deal about induction motors as ...
  A: I'll help as much as I can. But it appears that you have studied this topic more than I have. Motor ...
transistor7/10/2008
  Q: Ms.Steve Could tell us about the newest and latest applications of transistor? We'd be thankfull.
  A: The transistor is used in so many devices I can't possibly know the latest. Your cell phone probably ...
RE: Finding the resonant frequency of an object7/9/2008
  Q: Good day Steve! I am Drew from the Philippines. I am an undergraduate BS-ECE student and me and my ...
  A: An interesting and important task. There are too many land mines left waiting after hostilities are ...
physics7/8/2008
  Q: A bullet of mass 10g traveling horizontally at a speed of 100ms embeds itself in a book of wood of ...
  A: This is a problem for the principles of conservation of ___. First you need to use conservation of ...
ballast7/3/2008
  Q: My work is quite stressful and my way of de-stressing ( and you may find this weird),is to brouse ...
  A: Sorry that it's taken quite a while to get back to you. I haven't found much information about this. ...
the moon's gravity7/2/2008
  Q: With the moon's mass 1/80th of the earth's, why is its gravity 1/6th? Thanks
  A: It's true that the moon's mass is about 1/80th of Earth's. Newton's equation of universal ...
Magnetism and Electricity7/1/2008
  Q: Ok, I understand that electricity creates a magnetic field as it passes through a conduit (wire, ...
  A: If the current is an AC current, there are 2 ways that I can describe. One is a transformer. You ...
magnetism6/30/2008
  Q: Can you explain why a steady current like DC produces a magnetic field only..what is the link ...
  A: Your questions are very basic questions. As physicists discovered phenomena, they then tried to ...
Rotation speed6/29/2008
  Q: I'm a woodworker but have a question regrading the fan in my spray room. I'll list the parts I ...
  A: You're right about the circumference being involved. If the belt moves 10 cm over the small pulley, ...
falling objects6/24/2008
  Q: When a small pebble about the size of a marble, is dropped into an 8 inch cylindrical hole of a ...
  A: I assume that "without any affect of air movement" means that there is no air resistance. That means ...
RC Circuits6/16/2008
  Q: what are the equations to find the voltage across a resistor and capacitor of a RC Circuit in ...
  A: I agree with James J. Kovalcin. But a different explanation sometimes helps. So assume you have a ...
ROLLERCOASTER PHYSICS6/15/2008
  Q: I am in year 12 and have been asked to construct a model, working rollercoaster. I have built it ...
  A: If the P.E.=465,975 J when the rollercoaster is halfway down from the peak, the maximum P.E. (at the ...
Hit baseball: accel or de-acccel?6/13/2008
  Q: When a pitched baseball is well hit, does it accelerate from zero (the moment it was hit) for a good ...
  A: The baseball will not accelerate toward the outfield unless there is a net force acting on it toward ...
iPod6/11/2008
  Q: I have two questions about how iPods work. First of all, could you explain to me (in electrical ...
  A: I'm sorry, I don't know. I don't have and haven't used an ipod. I did some searches trying to find a ...
Magnet only pushes in ONE direction6/10/2008
  Q: http://www.youtube.com/watch?v=xb8wwkdtz0M Can you explain this ?
  A: I see only one thing that might explain why the magnet set near the disk, call that one m1, wouldn't ...
units and significant figures6/8/2008
  Q: Sir few very basic questions related to units in meausrement as we hav been introduced to units in ...
  A: It's good to avoid starting off unsure of the basics. Statements: 1) It may be just a legend, but ...
physics6/6/2008
  Q: time of flight,range of a projectile
  A: If you know any 2 of the parameters: time of flight,range of a projectile, and angle of take-off, ...
heat6/5/2008
  Q: A silver bar 0.125 meter long is subjected to a temperature change from 200°C to 100°C. What will ...
  A: The answer is clearly A. There's no way the bar would shrivel up as much as B,C, or D say (about 1 / ...
vectors6/4/2008
  Q: sir i want to know when we find torque = cross product of moment arm (distance of point of ...
  A: 1) The valid direction of the vector of a straight line force is obvious. It's the direction the ...
Physics Lab- how to name controls and variables6/3/2008
  Q: I'm designing a lab that talks about "energy relationships". I have created a lab, but I don't know ...
  A: I'm a little troubled by the setup of the experiment. I'll just point out some things and then go ...
Energy from Hydrolysis6/2/2008
  Q: I would like to know the energy return from hydrolysis. Let's say a person uses 100 kilowatts of ...
  A: According to Wikipedia (http://en.wikipedia.org/wiki/Electrolysis_of_water), the theoretical maximum ...
center of mass of the body6/1/2008
  Q: In which direction would the center of mass of the body migrate if the arms were raised overhead? ...
  A: If some of the mass of the body is elevated, the center of mass (c.o.m.) will be elevated. If some ...
online lectures.5/30/2008
  Q: im doing bsc physics major through correspondence. can you suggest me some "online video lectures" ...
  A: I didn't personally know of any, so I did a yahoo search: ["online lectures" "basic physics"] and ...
electricity5/29/2008
  Q: if a resistor wound then it acts like inductor how a single wire show different properties like ...
  A: Ampere's Law says that any current produces a magnetic field. The relationship between the current ...
Physics, Electricity, Circuits...5/27/2008
  Q: What's the diff. between a light bulb connected to the positive terminal of a battery and one ...
  A: If I have this right, in either case you have some wire, a switch, an ammeter, and a lamp between ...
Evaporation Rate5/22/2008
  Q: What molecular variables do you think affect the evaporation rates of liquids?
  A: I have several web sites for you to look at. ...
force5/21/2008
  Q: Why is it difficult to walk on a marshy land ? please explain
  A: You are doing a certain amount of work as you walk. When you walk in a marsh or on a sandy beach, ...
Tesla Coil Build5/20/2008
  Q: Dr. Johnson, I'm planning to build a tesla coil as a nice side project over this summer, and seeing ...
  A: It's good that you want to find resources to learn as much as you can. It is a dangerous goal. I ...
Egg Drop5/18/2008
  Q: I am doing a science project for school (high school) and for some reason I have to define some ...
  A: Sorry, I don't know "disturbing the forces". It sounds like a term from the Star Wars movies. It's ...
electrical science5/16/2008
  Q: draw one cycle of an a.c. waveform having a peak value of 325v at 50Hz. From the waveform, determine ...
  A: Draw a vertical axis at the left of your drawing space, label that "Voltage" with +350 at the top ...
Hooke's law5/13/2008
  Q: A 5000 kg truck drives over a pothole in the road that causes the truck to push down on all four ...
  A: Unfortunately your question got garbled somewhat. I got "½ kx2 = mg h". I think that box in ...
force5/12/2008
  Q: helo sir i hav some doubt related to reaciton force. suppose i hold a chalk on my hand out ...
  A: Yes this can be confusing. When you hold the chalk, all of the weight of the chalk is exerted on ...
conversion5/8/2008
  Q: how do i convert kilogram/meter to Newton/meter?
  A: Kilograms are the unit of mass and Newtons are the unit of force and weight. The relationship ...
Current versus Voltage5/4/2008
  Q: I'm trying to get my head around the idea of current versus voltage. By my way of thinking the ...
  A: Followup at the end. Your ideas are pretty close to true, maybe if I just add a few things it'll ...
voltage5/1/2008
  Q: 1. A circular coil of diameter 8 cm and consisting of 1000 turns is rotated in a 0.2 Tesla ...
  A: 1a. The magnetic flux density, B = 0.2 tesla, which is equivalent to 0.2 weber per square meter. ...
Momentum and spring constant4/30/2008
  Q: i need help! a block of mass m is attached to the end of a horizontally mounted spring of ...
  A: a) When displaced by xo, there is a spring potential energy spe = (1/2)*k*(xo)^2 When the block ...
Physics Misconceptions4/28/2008
  Q: Physics has never come intuitively for me. I somehow make little mistakes along the way that give me ...
  A: To help your intuition: If a relationship doesn't make sense, try to simplify it, or perhaps think ...
Physics Project Ideas4/27/2008
  Q: I am a senior in high school and in my physics class we have been assigned an end of the year ...
  A: I think your choice should be influenced by the interest you had in the various topics that you ...
resonant frequency4/26/2008
  Q: I just want to ask how can i construct a material of a specific resonant frequency? What are the ...
  A: During my electrical engineering career it was the mechanical engineers that were given the task of ...
Electrostatiacs4/25/2008
  Q: When we connect the positive terminal of the battery to the ground, then what happen to van de graff ...
  A: If the Van de Graaff generator you're asking about is like the one on this webpage, ...
pulley systems4/23/2008
  Q: for a horizontal pulley problem involving friction where you have a block c sitting on top of block ...
  A: OK, the way you have explained it, the task is to increase the friction between block a and the ...
egg Drop4/21/2008
  Q: i have to do the egg drop project for physics. My rules are i can only use 10 sheets or standardize ...
  A: I never did one of these when I was in school. Now I'm surprised to see how many variations on the ...
pulley systems4/20/2008
  Q: for a horizontal pulley problem involving friction where you have a block c sitting on top of block ...
  A: I'm not sure I've got the picture right. The tension on the string pulling on block a is the weight ...
Egg Drop4/19/2008
  Q: How would speed, velocity and acceleration affect my egg and it's container for my egg drop?
  A: Speed, and velocity; and the increases in velocity acceleration causes, are involved in the kinetic ...
egg drop4/18/2008
  Q: For my egg drop project I am supposed to explain how Newton's Laws of motion affect my prototype
  A: If you ignore air resistance during the fall, the only force acting on the egg is its weight. ...
force4/17/2008
  Q: Sir These are questions related to force 1) Any body falling under gravity accelerates with the ...
  A: 1) You could add an external force. A body can accelerate at a higher rate than 9.8 m/s^2, if it has ...
Applied Mathematics4/16/2008
  Q: What effect, if any, would the coriolis effect have upon a parachute descent? The initial ...
  A: Very little affect. The Coriolis effect is small to begin with. And a parachutist looses all the ...
Tangent question4/15/2008
  Q: tangent to y = x^2 when x = 2. Can you tell me which of the following is the correct answer? ...
  A: I'm sorry that this reply has taken me so long. I usually do better. The desired tangent to the ...
frequency/waves4/14/2008
  Q: 4. A bat, moving at 5.00 m/s is chasing a flying insect. If the bat emits a 40.0 kHz chirp and ...
  A: 4. The formula describing the Doppler Effect when both source and observer are moving with respect ...
Physics4/11/2008
  Q: An elevator weighing 2.00x10^5N is supported by a steel cable. What is the tension in the cable ...
  A: The elevator's weight can be written as W = 2.00x10^5N = m*g So its mass is m = 2.00x10^5N / g I ...
Sound Waves4/10/2008
  Q: 1) A string of mass 4 grams and length of 2.4 meters is forced to vibrate at a frequency of 120 Hz. ...
  A: 1a) The nodes are the points of the string that are not vibrating. Or you can say the points of the ...
relative vector4/7/2008
  Q: sIR I have not faced so much difficulty in understanding any topic as i am facing in understanding ...
  A: I found the site you referred me to have a good discussion. But I might have presented the vector ...
Physics4/5/2008
  Q: Abullet with a mass of 6.00g is fired through a block of wood on a frictionless surface. The ...
  A: Momentum must be conserved in collisions. (That's true whether it's an elastic or inelastic ...
final equilibrium4/4/2008
  Q: A track star goes into jump at 12m/s and launches at 20.0 degrees above the horizontal. What is the ...
  A: The problem is simpler because both components have the same specific heat. I'll work the problem 2 ...
Questiom\n4/3/2008
  Q: If a 60 W light bulb at 120 V is left on in your house to prevent burglary, and the power company ...
  A: I think you could have figured that out just by just looking at the units. Let me help you see how. ...
Science4/2/2008
  Q: A 10 ton truck is going down the highway at 60 miles per hour. It comes to a complete stop in 7 ...
  A: Boy, I dislike physics problems given in pounds and miles. And then they give the mass of the rotors ...
Electrical voltage4/1/2008
  Q: We take it for granted that the frequency is 60Hz and the voltage levels for transmission and ...
  A: Much of the answer is historical. Sticking to a choice because the investments already made are ...
A- physics (Electricity)3/31/2008
  Q: Please Sir could you kindly help me the theory behind the topic and diagram where necessary "AC to ...
  A: I think you are asking about a power system like (in principle) the old one described in this web ...
Magnetism3/30/2008
  Q: I would like to know about magnetic screening
  A: I'm not sure which application you're interested in. Consider the following sites. ...
Electromagnetism3/27/2008
  Q: If a car made of iron and steel moves over a wide closed loop of wire embedded in a road surface, ...
  A: Yes I believe it will alter the earth's magnetic field at that location. Iron introduced into a ...
force3/25/2008
  Q: sir thank you first for replying mu previous questions on force sorry for bugging you but since ...
  A: 1) Your question is typical of frequent confusion over just what Newton's 3rd means. I have seen a ...
please help!3/24/2008
  Q: 1.An athlete with a mass of 95 kg is found to have an apparent mass of 7.92 kg when submerged in ...
  A: First, I'm on a mission: Teaching people how to show squared and other powers in computer text. ...
force3/23/2008
  Q: sir few questions on force and force of gravity 1) Why does inertia of an object depend on mass ...
  A: 1) It's mass that makes an object resistant to changing its velocity. Being resistant to changing ...
simple generator3/22/2008
  Q: I am attempting to make a simple generator. Here's what I've done so far. I have coiled 3 small ...
  A: I'm almost sure, but just to be 100% sure, you mean you taped it with electrical tape? OK, good. ...
Rotational dynamics toppling&sliding3/19/2008
  Q: Broadly explain toppling and sliding with good number of examples involving calculations. Thanks.
  A: I need a more clear explanation of what you're asking about. Please send a followup. I guess I could ...
miscellaneous3/18/2008
  Q: sir few questions as i hav just appeared my class X physics exams and i am doubtful about few ...
  A: 1) It is good that you watch the units. They will often give you a clue if things are going wrong, ...
electricity3/16/2008
  Q: sir i hav one question , its really urgent. sorry for asking you this question last moment and ...
  A: OK, I hope this is quick enough after you posted the question. Your book is probably correct. Have ...
acceleration of gravity3/11/2008
  Q: it would be really nice if you solved this before March 19,2008! OK.....According to the ...
  A: I hope you intend for me to ignore air resistance. I don't know whether air would have more affect ...
thin film resistors3/10/2008
  Q: why would it be better to use a thin metal film resistor as opposed to a wire wound resistor for an ...
  A: The wire wound resistor can have some inductance. Although some of them are built to minimize the ...
dimmer for light bulbs3/7/2008
  Q: I would like to know what happens when you attach a 100 watt or a 300 watt light bulb to a dimmer ...
  A: There are different types of dimmers. The older, more crude type puts an adjustable resistor in ...
Physics3/6/2008
  Q: What is the cause of Earth's Gravity. How is it produce.
  A: Man's understanding of Gravity has improved throughout time. The first fairly good understanding was ...
opposite forces pulling a boat3/5/2008
  Q: How do you determine the opposite forces acting upon a boat in two opposite directions? The boat is ...
  A: I have to make some guesses here about what you mean. Here's what I will assume you meant: How do ...
modern physics3/1/2008
  Q: how can we understand from michelson and morely expriment that the speed of light is constant?
  A: The Michelson and Morely experiment wasn't designed to prove that c is a constant. And in fact it ...
physics2/29/2008
  Q: The space shuttle is in a 250-mile-high orbit. What are the shuttle’s orbital period, in minutes, ...
  A: The key to figuring this out is to understand centripetal acceleration. Newton's 1st Law says that ...
Chareable batteries2/28/2008
  Q: How have you been,after a brief sojurn,I am back with this question.I read an article about cell ...
  A: Good to hear from you again. Things are good here. The exploding thing is apparently true. It's ...
physics newtons third law2/27/2008
  Q: a. How much force does an 80.0 kg astronaut exert on his chair while sitting at rest on the launch ...
  A: a. The astronaut exerts his weight on the chair. W = m*g = 80.0 kg*9.8 m/s^2 Additional info: the ...
ac dynamo2/26/2008
  Q: sir this is related to ac current generated in ac generator 1) how is the output emf or volatge ...
  A: 1) Faraday's Law says that the induced emf equals -1 times the rate of flux change. The way that's ...
motion2/25/2008
  Q: what is motion uniformly accelerated?
  A: That means that the velocity is increased the same amount each second. For example: Say you're ...
vectors2/24/2008
  Q: You are a pilot on an aircraft carrier. You must fly to another aircraft carrier, now 1450 km at 45 ...
  A: I'm not sure how to interpret "at 45 degree of your position". I'm going to guess that means it's NE ...
force2/23/2008
  Q: sir i wanted to ask few questions thought it is not of your subject expertise but i think you would ...
  A: 1) If you were buying 1/4 kg of peanuts and the scale made an error or 1%, maybe you were gypped out ...
Energy2/22/2008
  Q: how are energy and electricity related?
  A: It's like the relationship between fruit and apples. Energy comes in many forms. One of the forms ...
general physics2/21/2008
  Q: A small ball rolls around a horizontal circle at height y inside a frictionless hemispherical bowl ...
  A: This is an interesting question. Too bad the "as shown" you mentioned didn't show anything. But I ...
Physical Science2/20/2008
  Q: What are red foxes? Consumers, Herbivores,omnivores,producers,carnivores, and/or photosynthesizers?
  A: Wikipedia says that the red fox (the 4 legged fox) is a member of the order Carnivora. But then they ...
Centrifuge force against Gravity2/18/2008
  Q: Not to go into too much detail here, but I need some help with my project. I have built a machine ...
  A: There's a cable in the top springs that restricts those springs from stretching as far as they would ...
Centrifuge force against Gravity2/17/2008
  Q: Not to go into too much detail here, but I need some help with my project. I have built a machine ...
  A: That thing really spins doesn't it? I'd hate to be in the way if one of the weights broke loose. I ...
What exactly are "flames"?2/16/2008
  Q: What exactly are "flames"? From what I've read about, it's where atoms are rearranging, with a net ...
  A: Interesting question. I had never studied, or thought hard about, just what flames are. Perhaps my ...
energy2/14/2008
  Q: Sir i have few questions. please donot consider these questions as homework questions as i am ...
  A: Followup is at the bottom. What you have plotted looks like what you might have plotted in a math ...
Tennis Net Tension2/13/2008
  Q: I'm wondering if you could help me with a problem im having. I'm currently mid process of designing ...
  A: I'm curious how you determined the force applied when a hard serve hits the net cord head on. Assume ...
symmetrical pi attenuators2/12/2008
  Q: When it comes to a schematic for a symmetrical pi attenuator, all I have been able to find is the ...
  A: I wasn't sure if the term symmetrical had more than the obvious meaning. So I found the following ...
physics2/11/2008
  Q: A 110 g block is dropped onto a relaxed vertical spring that has a spring constant of k = 3.0 N/cm ...
  A: a) If it weren't for the spring, the block would continue to increase its speed, therefore also its ...
space motion2/10/2008
  Q: In a test of a new missile defense system, a missile is fired on a trajectory that would directly ...
  A: The center of mass, COM, of the incoming missile will still land on its original target. So the only ...
Acceleration question2/6/2008
  Q: Felix steals for second base running at a speed of 4.20m/s. He slides into second base from a ...
  A: When you used the equations d=rt and d/r=t you found the time that it would have taken Felix if he ...
kinetic energy2/5/2008
  Q: if a mouse and an elephant both run with the same kinetic energy, can you say which is running ...
  A: The equation for kinetic energy is KE = (1/2)*m*v^2 where m is the mass and v is the velocity of the ...
SI unit2/4/2008
  Q: sir I am in 9 th grade. I want to ask you a question 1) We are learning SI units, can you tell me , ...
  A: 1) Two reasons I can suggest. To continue using units and values for those units that had been ...
Current question2/3/2008
  Q: I have a question regarding current through a water layer. The answer that i am getting for this ...
  A: I can see 2 traps that might have tripped you up: 1. The units of length need to be made ...
Drag Force1/30/2008
  Q: How to calculate the drag force of the human body in the water when you swimming?
  A: There may be formulas that try to yield an approximate value. Drag would vary with speed of swimming ...
Electricity1/26/2008
  Q: In reference to the electrical feed to a house, one lead is +110 and the other is -110 volts. The ...
  A: To say one lead is +110 and the other is -110 volts is an oversimplification. I started out looking ...
static electricity1/24/2008
  Q: One question on work and power 1) Which body of the two having power 150W and 200W can do more work? ...
  A: Ahh, I see your point. I agree with you, given any task where any amount of work (Joules) is ...
static electricity1/22/2008
  Q: One question on work and power 1) Which body of the two having power 150W and 200W can do more work? ...
  A: 1) A watt is a J/s. Each second, the 1st body has 150 Joules that it can "spend" doing work. The ...
force1/20/2008
  Q: sir i hav been trying to ask you a question but always i found you maxed out for past one week. can ...
  A: Sorry that you've had trouble finding me available. I accept only one question a day. At allexperts, ...
generators1/19/2008
  Q: I build water wheels and am playing with electric production. I am looking to drive a 60-100 amp ...
  A: If you have a load on the alternator that is drawing 60 amps, the power out of the alternattor is ...
Hamster powered night light1/15/2008
  Q: I am doing a science project on making a hamster powered night light, and I am in 8th grade. We are ...
  A: That sounds like a fun project. Also a bit challenging for the 8th grade. You must be an advanced ...
Physis1/9/2008
  Q: what's the best way to do a physics project about Free-Fall?
  A: That depends on what you want to learn about Free-Fall. Do you want to verify that falling objects ...
electrcity1/7/2008
  Q: sir i hav one doubt regarding a numerical in teh following circuit diagram we hav to find teh ...
  A: >why are they connected like this?< Yes, if you are using a number of 1.5 V cells to build a voltage ...
Egg Drop Project...Please Answer!!!!!!!!1/4/2008
  Q: I am doing the the egg drop project and i can use any material except bubble wrap and styrofoam. And ...
  A: This project has been discussed many times here at allexperts. I went to page ...
despersion1/3/2008
  Q: Is despersion of sound is posible like dispersion of light?
  A: Dispersion of light is obtained by sending a beam of light through a prism. The beam can be shown to ...
question1/2/2008
  Q: if he comes to rest 5.0 m beneath the surface determine the average resistance force exerted on him ...
  A: I don't see how this can be worked with the data given. The height the diver dropped from would ...
water pressure12/31/2007
  Q: If a pressure sensor is placed underwater at a given depth, say… ten feet, and a twenty foot wave ...
  A: I don't have specific knowledge or data about this so I have to rely on instinct, or what seems ...
A/C Current12/30/2007
  Q: I have a very basic question regarding 110 volt a/c current. From what I understand the a/c changes ...
  A: >the voltage is always on the hot wire but changes from 120 to 0,back to 120 etc< Well, I need to ...
Is neutron-neutron fusion easier to facilitate than proton-proton fusion?12/27/2007
  Q: Neutron-neutron fusion is an example of nuclear fusion because neutrons are nucleons. Is it possible ...
  A: This is well outside my experience and expertise. However I've been working on your question hoping ...
Gyroscope12/25/2007
  Q: I want to know how gyroscope works? ,different types of it ,what are related equations?,useful sites ...
  A: When I first started work after college (1968), my first assignment was related to gyroscopes. I was ...
energy loss of a projectile12/23/2007
  Q: I am submitting two related questions. I am 52 years old, so this is not a kid's homework project, ...
  A: Your subject implies that I should consider air resistance. First I'll ignore air resistance. If you ...
free energy ???12/22/2007
  Q: what can be put between two magnets to stop the force
  A: One way is to put a lot of distance between them. That probably wouldn't work for whatever you're ...
?12/20/2007
  Q: If an astronaut is in space, is it's mass the same as it is when it's on Earth?
  A: Depends on diet. If it eats more than enough to maintain the normal amount of mass, it might get ...
sound12/19/2007
  Q: Sir i hav a problem sum which came in my exam I know that the frequency of a string is inversley ...
  A: One error I see may be just in the version you wrote up for me about how you worked it: "velcvit of ...
physical science12/18/2007
  Q: Can an object have mechanical energy without having momentum?
  A: Yes. Two examples: Newton's apple had gravitational potential energy before it broke loose from ...
newton's laws12/17/2007
  Q: applications of newton's laws in our daily lives and studie
  A: Newton's 1st: When you put your book on your desk, it stays there without moving (even if your desk ...
doppler effect12/16/2007
  Q: In doppler effect if the observer and the sours are located at the top of a train that is moving<is ...
  A: This was an interesting study. I hadn't thought this through for many years and it took me some time ...
Egg Drop Question12/13/2007
  Q: what we now need to do is to determine the minimum time the egg has to stop to survive. What I do ...
  A: Knowing the max force that can be applied to the egg and the mass of the egg, you can find the max ...
science12/12/2007
  Q: Gas a is composed of diatomic molecules (two atoms to a molecule) of a pure element. Gas B is ...
  A: I am sorry that this is late. The equation of state for an ideal gas says that p*V = n*R*T where p ...
high voltage electric shock12/11/2007
  Q: can we receive an electric shock from the overhead distribution wires fixed up by the company? if so ...
  A: Air is good insulation. If there is an air gap (of more than a few millimeters) between you and the ...
Physics12/10/2007
  Q: Can you help me with thisA 70.0kg box is pulled across a frictionless surface by a 300N force at an ...
  A: I'm sorry this is late. You need to find the downslope component of the box's weight. Components ...
Physics12/6/2007
  Q: we are a groups of physic teachers following a professional development course bewilder happy if you ...
  A: A quick answer is that Geophysics is the science of the earth and its environment. Geophysics has ...
Newton's Cradle12/5/2007
  Q: When you place a finger in between the middle of the Newton's cradle, somehting strange happends. ...
  A: The operation of Newton's cradle requires that the balls be elastic, equal shape, and equal mass. ...
light12/4/2007
  Q: I'm not quite sure if your the right person to ask for this question but I was just wondering, ...
  A: You are right. Gravity affects light. The effect is that if a light beam passes close to a body with ...
bridge jumping impact force into water12/3/2007
  Q: "hello Im a adventure film maker.(www.myspace.com/flyingfatmanproductions) I have made a movie about ...
  A: My pleasure. That was a fun question. Bear in mind that pressure is a significant factor in the ...
bridge jumping impact force into water12/1/2007
  Q: "hello Im a adventure film maker.(www.myspace.com/flyingfatmanproductions) I have made a movie about ...
  A: I have to disagree with your velocity figure. In free-fall, if you can ignore air resistance, the ...
physics11/30/2007
  Q: Why is there no net force in constant speed Please provide a different answer than just the simple ...
  A: The easy answer is that if the net force were non-zero, then that net force would cause ...
force and energy11/25/2007
  Q: have two questions whose answers i am not geting. can yoy please help me. 1) The momentum of a body ...
  A: The force of 447.2 N was applied only for the 0.5 s period. That force was applied by the earth ...
Questions about magnetic analogs of electricity.11/24/2007
  Q: Dielectric strength and ohm [electric resistance] are electric entities. What are their magnetic ...
  A: Dielectric strength and electric resistance are both a measure of the ability of the substance to ...
electricity11/23/2007
  Q: if a point charge is released in a non uniform electric field with field line in the same direction ...
  A: Just to be clear, I'm going to assume you mean that it's the original velocity of the charge that is ...
Fluids11/21/2007
  Q: "The cross-sectional area of the faucet is 1.8x10^-4m^2, and the speed of the water is 0.85 m/s as ...
  A: The volume of water passing through any and all cross sections in a second have to be equal. That's ...
force and energy11/20/2007
  Q: have two questions whose answers i am not geting. can yoy please help me. 1) The momentum of a body ...
  A: Well, I'll show the method and equations. Giving the answer is something I try to avoid. I prefer to ...
Why are magnetic field lines always depicted as pointing from north to south?11/18/2007
  Q: Southern magnetic energy is emitted from the side of a magnet taking in the lines of force. Northern ...
  A: Magnetism is present in an area if there is some force that tends to make a test magnet align in a ...
Explain pls.11/14/2007
  Q: Explain connection of circuit to physics?
  A: Physics has several fields. Electricity is one of them. Physicists study the phenomena and determine ...
angular momentum11/13/2007
  Q: We have a project to do in physics (first year university) about angular momentum. That is the ...
  A: I see why you say that hurricane doesn't have mass. Before the hurricane came to a particular place, ...
Physics11/12/2007
  Q: Hey Steve, How have you been? I can lift a bag off the floor,a weightlifter can lift more than his ...
  A: Some people like excitement while on vacation. Roller coasters, scary movies ... natural disasters ...
ac theory11/11/2007
  Q: im after some advice about the foolowing question. a resistor of 250 ohms is conected in series ...
  A: Yes you need to come up with net impedance. It's not as simple as 100 / 250 = 0.4 amps. That's what ...
physics11/10/2007
  Q: Suppose air friction acting on a car increase as kv^2. What is engine power needed to keep the car ...
  A: Power is the rate that work is being done P = W/t where the amount of work W is done in time t. ...
centrifugal force11/8/2007
  Q: why don't we experience centrifugal force due to the rotation of the earth?
  A: I prefer to talk about centripetal force. Centrifugal force is somewhat controversial. In the ...
Simple Machine Design Question11/7/2007
  Q: I'm trying to figure out how to design a simple machine with the following specifications: There is ...
  A: The downslope force due to the weight of mass M2 being on the slope is Fds = M2*g*sin20 The static ...
hello11/6/2007
  Q: you exercised by working for 15 min. on a treadmil A). what is you velocity relative to the trail ...
  A: A) Trail, do you mean the tread of the treadmill? If so, your velocity relative to the tread is the ...
Physics11/5/2007
  Q: Hey Steve, How have you been? I can lift a bag off the floor,a weightlifter can lift more than his ...
  A: Let's start by putting you in that cage! If you pull on the rope, you will first start climbing the ...
electromagnet dc motor11/4/2007
  Q: How should i build a dc motor, if i want two electromagnets instead of permanent magnets, and i want ...
  A: I don't have personal experience from my career on motors. So I had to do some research. Yes you can ...
Bike riding and wind resistance11/2/2007
  Q: I have a question. If I ride 15 mph in an upright position (about a 12 o'clock position), how much ...
  A: According to http://en.wikipedia.org/wiki/Wind_resistance, the force of wind resistance, (or more ...
density question10/31/2007
  Q: I need to know how the density of an object will be affected if the volume of an object is ...
  A: Density is mass (sometimes weight) divided by volume. Density = mass / volume The units are ...
Taking Off ; Newtonian Mechanics10/25/2007
  Q: I am uncertain what formula I should use to solve this question. Could you help me out? " A jumbo ...
  A: You know the original velocity, Vo, the final velocity, Vf, and the distance, s (sometimes the ...
Continuity Equation?10/24/2007
  Q: Use the continuity equation to explain how jet engines provide a forward thrust for an airplane. My ...
  A: I didn't know of (or didn't remember) the Continuity Equations either. A search yielded several ...
Pondering science project10/23/2007
  Q: If you place different weights on a skateboard and roll them down an inclined plane, gravity will ...
  A: "Rolled farther" ... I assume you are talking about the skateboard rolling farther on the level ...
physics10/21/2007
  Q: when alternating current flows through an inductor, voltage leads current by phase angle 90 ...
  A: The affect of inductance is to resist any change of the current flowing through it. When the voltage ...
Newton's law of cooling10/20/2007
  Q: A cup of coffee is taken from a coffeemarker at 96C and left on the office table. In the ...
  A: Newton's law of cooling is an approximation which holds well if the cooling body can be assumed to ...
forces on 3 connnected blocks10/19/2007
  Q: There are three blocks on a frictionless surface. Block one (1.0kg)is connected to block 3 (4.5 kg) ...
  A: The 3 blocks (total mass = m123) are all connected in some way, so all have acceleration of the same ...
SUVAT10/18/2007
  Q: I am struggling to rearrange the equation s=ut+(at^2)/2 to find time. please help!
  A: I assume that you know s, u, and a. If so, this will become a quadratic equation. I imagine ...
physics10/17/2007
  Q: A 1.5 kg ball and a 2.2 kg ball are connected by a 1.0 m long rigid, massless rod. The rod is ...
  A: I'm sure you could do this if it were a mass sliding on a table. What friction would bring it to a ...
clockwise or counterclockwise?10/16/2007
  Q: I've just started learning about the torque, so I'm still confused about some fundamental stuff. I ...
  A: I think I can best explain if I set up a situation and analyze it. Consider an uniform steel bar, 3 ...
heat10/14/2007
  Q: Can you explain me the following questions 1) Why does the melting point of ice decreases with ...
  A: I did not know much about either topic so I searched the web. 1) This collection of websites ...
kinematics10/13/2007
  Q: A boy standing on the ground 20m from a building throws a snowball into a window 15m above the ...
  A: I've added a followup at the bottom. Go there to pick up a modification of my answer. Since it went ...
physics10/10/2007
  Q: I have been trying these two problems with no luck any help is appreciated Thank you 1. A 60 kg ...
  A: 1. Since the skydiver is traveling at constant speed, there is no net force acting. The skydiver's ...
electric toothbrushes10/9/2007
  Q: How does the charger for my electric toothbrush work? It sits in a stand to get charged, but there ...
  A: You're right, it's the phenomenon of electromagnetic induction. DON'T DO ANY OF THESE STEPS without ...
Physics Tension Help?10/8/2007
  Q: I have a question regarding this problem. I have tried using the formula mv^2/r but is that not ...
  A: It's true that you should use the formula mv^2/r. That is the centripetal force that is required to ...
about pressure and electricity10/7/2007
  Q: i wanted to ask you wether we can convert applied force into electricity or not if yes how please ...
  A: Yes we can. If we can include torque (which is a force applied to a lever arm to cause rotation) in ...
Force and accelerations - Newton10/6/2007
  Q: I have a question from my homework: There are to blocks A and B. The mass of A is 20kg and the mass ...
  A: So if I have it pictured right, I guess block A could just sit on the table and block B could go up ...
Heat10/5/2007
  Q: A temperature of 200 F is equivalent to approximately A. 37.8 C. B. 93.3 C. C. 232 C. D. 840 C.
  A: I'm sure you know a few facts that you could use to answer this yourself. Let me remind you of some ...
Projectile10/4/2007
  Q: The lob in tennis is an effective tactic when your opponent is near the net. I consists of lofting ...
  A: I have to assume that the lob is launched essentially at zero altitude. I'm going to give you advice ...
velocity10/3/2007
  Q: I've been trying to find the equation for the velocity of an object dropped from a certain height, ...
  A: If you have an expression for position, x, versus time, t, the 1st derivative (dx/dt) is velocity, ...
Problem about Projectile Motion10/2/2007
  Q: I need help understanding this problem specially the part where I have to calculate the range ...
  A: You can separate the initial velocity of 65.2 m/s into horizontal and vertical components. Vix = ...
physics9/30/2007
  Q: when you are standing on the ground. how much upward force is exerted on you by the earth?why does ...
  A: You are pushing down on the Earth with a force equal to your weight. (This is the same force you ...
acceleration and tension9/27/2007
  Q: A block is resting on a horizontal table and has a weight of 422 N. It is connected to a block ...
  A: The 2 blocks will undergo acceleration of the same magnitude since they are tied together. #1 goes ...
Elelctricity and Electronics9/26/2007
  Q: first I would I to say thank you if you can help I've been struggling with this lesson. 1. ...
  A: I disagree with several of your answers. I think you need to hit the book. I considered refusing, ...
electrical resistance in wires9/24/2007
  Q: 1 what effect does connecting an ammeter and voltmeter to a circiut have on the experimantal ...
  A: 1 Often in scientific observations, the method of making the observation changes the behavior. A ...
voltage drop9/23/2007
  Q: I am trying to find out the p.d. accross a resistor of 250 ohms and a inductor of 1.5 H. Both ...
  A: As a guy who worked in electronic labs for 32 years, I can say that "potential difference" and ...
Physics Help Please9/20/2007
  Q: I have started working on this problem and know that the moon rock will fall towards the moon and ...
  A: Some data first: Radius of Earth = 6.371*10^3 km. Mass of Earth = 5.983*10^24 kg Radius of Moon = ...
physic9/18/2007
  Q: can a rope ever be 100% horizontal?
  A: Well, not unless it's laying on a 100% horizontal table!! I assume you mean it's stretched out ...
Physics stopping distance9/16/2007
  Q: The minimum stopping distance for a car traveling at a speed of 30 m/s is 60 m , including the ...
  A: You need to analyze the ability of the brakes. So you should subtract the distance traveled during ...
fuse9/15/2007
  Q: i have a question regarding the electric fuse. An electric currentof rating 3Kw,250V.I want to know ...
  A: The heating element in the electric kettle will be primarily pure resistive. Power in that case is ...
physics problem9/14/2007
  Q: I have tried this problem and cannot figure it out. Any help would be greatly appreciated! Thank ...
  A: Since the acceleration is perpendicular to the original eastward velocity, the eastward velocity ...
Electrical circuits9/11/2007
  Q: Why would it be better to use the variable resistor rather than the potentiometer?
  A: I generally use the terms interchangeably and generally abbreviate to "pot". But there is a ...
Torque on a rotating drillstring9/9/2007
  Q: Please Help - I am stuck on this one. How do I calculate off-bottom and on-bottom torque on a ...
  A: I screwed up. I prepared an answer and must have fumbled the process of sending it out. I just now ...
Torque on a rotating drillstring9/7/2007
  Q: Please Help - I am stuck on this one. How do I calculate off-bottom and on-bottom torque on a ...
  A: Sorry, I'm going to have to ask you for more information. I didn't know what a drillstring was so I ...
Waves9/6/2007
  Q: 1)What is the property of a Transverse wave that allows it to travel thru a vacuum as opposed to a ...
  A: 1) Not all transverse waves can go thru a vacuum. The wave on a violin string is transverse, but it ...
Physics9/4/2007
  Q: I am having trouble understanding what to do with the information given in the following equations: ...
  A: Nothing is said about wind resistance in these questions so you should assume that you are supposed ...
Wine9/3/2007
  Q: You will like this one :) I attended a wine appreciation talk recently and was told that the ...
  A: I didn't know why it was there. I was just vaguely aware that there was a dimple at the bottom of ...
Physical Science9/2/2007
  Q: What Is Simple Machine and Complex Machine ? I need some examples of Simple Machines, and Complex ...
  A: The 1st of the websites below gives definitions. The definition of complex machine isn't as clear as ...
stressed with this question8/31/2007
  Q: .. ok it says : instructions for finding buried gold, go 83.9 paces at 188 degrees, turn to ...
  A: Sorry for this tardy response, it's been a busy week-end. >"between the limits of -180 degrees and ...
graphing problem8/30/2007
  Q: How do I go about drawing a position versus time graph for this problem? A police car is at rest ...
  A: I'm going to start out using equations, then maybe we'll have a function to graph. The speeder is ...
liquid pressure8/29/2007
  Q: Sir i have few questions related to pressure in iquids I am showing three diagrams , i hope it ...
  A: The figures show different size bases for each. And that's OK, water at the bottom of a 10 meter ...
MOTION8/28/2007
  Q: TWO BOATS 'A' AND 'B' MOVE AWAY FROM BUOY ANCHORED AT THE MIDDLE OF A RIVER ALONG MUTUALLY ...
  A: Yes, that's what 'N' TIMES GREATER means. If the river current is 1 m/s, and N is 3, the boat speed ...
mechanics8/26/2007
  Q: I want to ask this question. A chain of mass M and length L held vertical by fixing its end to a ...
  A: Let's call the point in the chain that is a length y from the support, point Y. Since there is no ...
Physics(Projectile motion)8/24/2007
  Q: Two guns are pointed at each other,one upwards at an angle of 30 degree & the other at the same ...
  A: At the muzzle velocities involved, the time is going to be very short. Therefore the distance the ...
bulb8/23/2007
  Q: why is a bulb filled with inert gas? I know that it deposits the evaporated tungsten back but HOw? ...
  A: I'll explain briefly, but the links below do a complete job of discussing the topics. >inert gas ...
fluid dynamics8/22/2007
  Q: Why canals posses 'V' shaped cross-section instead of 'U' shaped cross-section?
  A: I'm afraid I haven't been able to confirm that V shapes are common. Quoting from ...
Electromagnetic Field8/21/2007
  Q: How are you?I am doing a course in electromagnetics.I have a question relating to transmission ...
  A: Good to hear from you again -- I'm fine thanks, hope you are doing well too. I feel I need to ...
Electric fields8/20/2007
  Q: based on a magnet [or something with a magnetic field] passing thru a coil, which generates a ...
  A: >field oscillates from zero to its maximum That would be effective. But other changes in the field ...
Electric fields8/19/2007
  Q: based on a magnet [or something with a magnetic field] passing thru a coil, which generates a ...
  A: This process is called induction. The formula for the induced emf e (this should really be an ...
Suplemontry quatites8/18/2007
  Q: In some books I found that radian and stradian are categorize into third type of quantities known as ...
  A: The Systeme International d’unites (SI) conference decided on 7 fundamental units. Combinations of ...
voltage fluctuation8/17/2007
  Q: 1) IF i connect a voltmeter between the socket[neutral and live] at my home the voltage shown is not ...
  A: Sorry I missed your time target. I didn't read this until morning my time. 1) Ohm's Law says that V ...
linera and rotational motion8/16/2007
  Q: if i have a roller (cylinder, pencil)on the table a I move it by rolling my ruler over the top of it ...
  A: Look first at the pencil with respect to the table. You can leave the ruler out of it for now. If ...
Physics reason for drive on left or right8/12/2007
  Q: I would like to know which way is more sensible in terms of physics that driving on the left of the ...
  A: I don't think I'm going to lean either way. The Coriolis effect is weak and would have the opposite ...
electricity8/5/2007
  Q: sir i want to know that in a bulb, does all the kinetic energy of the electrons or charge gets ...
  A: Regarding your 1st q, it's better to think in terms of electric energy. (The electrons still have ...
electricity8/2/2007
  Q: i want to know that the current coming to house is alternating current. now there are three wires ...
  A: Yes, the current (electrical power) coming to your house is AC. It's more proper to say that the ...
help with this calculation8/1/2007
  Q: This question was sent to you recently; I received an answer from another source; do you agree with ...
  A: I can agree with that other answer if I use those assumptions. You didn't say anything about ...
electricity7/27/2007
  Q: why is the resistance of the bulb filament kept og very high resistance? I know that in a bulb, the ...
  A: Consider a 100 Watt bulb intended for 110 Volt power. Voltage (V) is the force that causes charges ...
Huygens double slit exp7/26/2007
  Q: If I have an 11kv power line and put a copper mesh (shaped like a metal fence ) a few feet under ...
  A: I may be badly misunderstanding your questions. But let me proceed. For an induction of current in ...
Forced collision7/24/2007
  Q: When two freely moving masses collide the outcome is easily determined. What happens when the first ...
  A: Hmmm, that's a good one. Let's limit this to collisions in one dimension. We have collision formulas ...
resistance7/23/2007
  Q: 1)why does the internal resistance of a battery decrease with increase in the temperature? because ...
  A: I think the answer to all 3 parts is efficiency of the chemical action in the cell. 1) I wasn't ...
Huygens double slit exp7/22/2007
  Q: If I have an 11kv power line and put a copper mesh (shaped like a metal fence ) a few feet under ...
  A: (followup below) The main reason I'm writing right now is to ask for time to come up with a better ...
motion7/21/2007
  Q: A ball is thrown vertically upwards from the ground with an initial velocity of 50m/s.What is the ...
  A: After being thrown up at original (or initial) velocity Vo, the ball is decelerating at g = -9.8 ...
water_motion7/19/2007
  Q: I have a curious question.Imagine a bullet was projected from a still helicopter (straight down, in ...
  A: The bullet arrives with high speed at the surface of the water. It is suddenly subjected to a large ...
electricity7/18/2007
  Q: helo sir I was reading the chapter on electric potential. Now the elctric potential in all books is ...
  A: Well it turns out that my book defines potential differently. Paraphrasing slightly what it says: ...
electricity7/16/2007
  Q: sir i hav few questions on electricity 1) why does a thin wire offer more resistance to current than ...
  A: 1) A wire contains many free electrons moving randomly around in a disorganized manner. When you ...
physics-mechanics 2 questions7/15/2007
  Q: random questions out of the text i cannot seem to wrap my mind around. First year University Physics ...
  A: Followup: While I was waking up this morning my mind was bouncing form one topic to another and ...
physics help7/14/2007
  Q: (1) A projectile fired from a gun has initial horizontal and vertical components of velocity equal ...
  A: This question tests your understanding of concepts. Gravity acts vertically. The projectile starts ...
physics7/13/2007
  Q: The density of ercury is 1.36 x 10^4 kg/m^3. What is the mass of a 4.00x 10^-4-m^3 sample of ...
  A: The formula for density is D = M/V where D is density in kg/m^3, M is mass in kg, and V is volume in ...
sound7/11/2007
  Q: sir i know that this may not really be related to your field, its related to resonance of sound, but ...
  A: It's true that this isn't my field and I don't often think about acoustics, but I can get my mind to ...
Hi Steve7/10/2007
  Q: Its me again with a follow up question on my earlier question ref air pressure. one atmosphere at ...
  A: Yes, one atmosphere at sea level is developed the way you describe. And I agree, the weight of the ...
fluid pressure7/7/2007
  Q: why pressure inside a fluid is same in all direction?It's due to gravitaion but it's only downwards.
  A: Consider a modification to a teapot. Remove the lid and build a cylindrical 3 meter vertical ...
Physics7/4/2007
  Q: I refer to the experiment where you fill a glass to the brim with water,then place a piece of thick ...
  A: I tried this out (got quite wet) to study the variables. I don't think I had the right type of ...
physics for living7/3/2007
  Q: I'm wondering if you can name some great books on physics for non-physicists. There are two types ...
  A: It looks like "Physics for Future Presidents" meets your needs for an overview of physics quite ...
AC POWER6/30/2007
  Q: In AC RLC circuits the apparent power S is VI and the real power is VI cos theta and reactive power ...
  A: Perhaps it's hard for me since I don't know the context in the texts you have found give the ...
Electricity6/29/2007
  Q: Hey I have been working as a land surveyor for a while and we are currently on a project under a ...
  A: I disagree with your statement that you need a complete circuit in order to generate electricity. ...
AC POWER6/27/2007
  Q: In AC RLC circuits the apparent power S is VI and the real power is VI cos theta and reactive power ...
  A: The question on apparent power made me dig. Thank you for the challenge. I think this website will ...
physics- average force6/26/2007
  Q: what is the average force required of the brakes in a 1200kg car in order to come to rest from ...
  A: In order to come to rest, Vf = 0, from original velocity Vo = 60,000 m/3600s in a distance s = 150m, ...
About Newton's 3rd law6/25/2007
  Q: As u know that action and reactions are equal and opposite and also act on two DIFFERENT bodies!! ...
  A: I agree, that wasn't one of my best answers. Let me try again. Newton's 3rd is often misunderstood. ...
Question about capacity of telephone lines6/24/2007
  Q: I am on reading a article about Loading Coil on a telephone line . It is used to extend ...
  A: The website you referenced says "Plain old telephone systems (POTS) telephone line consits of one ...
reply soon...6/21/2007
  Q: my Q is AC power supply is provided to our homes from grid station, but there are many home ...
  A: One of your home appliances is your computer. (Also radio, TV, cordless phone, microwave oven ...) ...
Motion6/20/2007
  Q: An object is pushed along a rough horizontal surface and released. It slides for 10.0s before coming ...
  A: The part of the slide that we know most about is the last 1.0 s of the slide. Let's analyze that ...
Pendulum Damping6/19/2007
  Q: I found from the internet that the equation for decay in the amplitude of a swinging pendulum is :- ...
  A: So in the hypothesized formula, I believe (if the parentheses haven't overwhelmed me) you could say ...
electricityandelectronics6/17/2007
  Q: electrons are emitted from a conductor when the conductor is
  A: I found several websites that should help you with this. ...
Pendulum Damping6/13/2007
  Q: I found from the internet that the equation for decay in the amplitude of a swinging pendulum is :- ...
  A: I'm sorry it took me some time to reply. But it's a good thing I didn't send my initial reaction to ...
Snap and Clap6/12/2007
  Q: What causes the sound when fingers snap or hands clapping?How different is that from the rumbling ...
  A: This is an interesting question. When things are quiet, the pressure of the air around us is pretty ...
Electromagmetic shielding6/11/2007
  Q: My friend is a medical doctor.He prefers to sleep on a mat on the floor as he has problems with his ...
  A: Non-ionizing radiation is believed to be harmless when the intensity is below the level of heating. ...
velocity of microwaves6/10/2007
  Q: what is the velocity of infrared microwaves
  A: In free space, all electromagnetic waves travel at c = 3.00*10^8 m/s. Perhaps you meant to ask ...
Induction6/9/2007
  Q: I have been told by some electrical people that a human can only produce one kilowatt per hour ...
  A: Sorry, but the quick answer is "No". I'm going to try to explain. I hope you have ridden a bicycle ...
Baloons6/8/2007
  Q: My daughter asked me yesterday after her helium baloon flew off..how high will it go?
  A: I won't be able to give you an altitude with great confidence. I can say (assuming no up/down air ...
questions about physics (heat)6/7/2007
  Q: 1. The transmission of heat requiring the movement of a liquid or a gas is A. conduction. ...
  A: I can help you with some of them, but I'm not an auto mechanic or refrigeration technician. Surely ...
plzz reply soon6/5/2007
  Q: What will be the direction of electric field in each of following circumstances: 1.in the middle of ...
  A: 1. E=F/qo where E and F are vectors. Direction of electric field can be determined by thinking of ...
Mechanics5/31/2007
  Q: Why a person bends in a downward direction while lifting heavy load?
  A: Well I guess it's so that if the person graps hold of the heavy load while bent over, then when ...
Physics5/30/2007
  Q: 1. T F A scientific fact is an educated guess. 2. T F Even if evidence is found which ...
  A: 1. We start with an educated guess which we call a hypothesis. After several studies and/or tests ...
waves5/29/2007
  Q: whats the effect of electromagnatic waves on the human brain?
  A: I don't really know. There have been many articles by experts and pseudo-experts. On this topic, I ...
Force of Drag across a Moving Body5/27/2007
  Q: I'm trying to determine the force of drag across a moving body. Can you provide me with a general ...
  A: I have a number of wegsites for you to look at. I believe they will answer your questions. drag ...
theory of relativity5/26/2007
  Q: Tell any practical application of special theory of relativity
  A: If you mean practical from the viewpoint of the banker, History teacher, or medical doctor, I think ...
Question about Sound- Physics5/23/2007
  Q: Sir, if frequency of two sounds are equal can u say that u r same? i want to know the parameters ...
  A: Instead of using the question method, there's another way to send positive feedback. As you read ...
plzzz reply me soon.....5/22/2007
  Q: questions are: Q1. A car goes along a section of road shaped like the letter S. The speed of the car ...
  A: I haven't replied to all of them. The ones towards the top were easy. But I spent some time thinking ...
electricity5/21/2007
  Q: Three rigid rods are joined to form an equilateral triangle ABC of side 1 m. Three particles ...
  A: What I was thinking of was the way the charges are attached. The charges are at the vertices. If ...
Question about Sound- Physics5/20/2007
  Q: Sir, if frequency of two sounds are equal can u say that u r same? i want to know the parameters ...
  A: Ahh, sorry that I misunderstood. First, about the Doppler effect: to reduce the amount of the ...
electricity5/19/2007
  Q: Three rigid rods are joined to form an equilateral triangle ABC of side 1 m. Three particles ...
  A: I'm going to assume you intended to say "The resultant <force> on the charged <particle> at A has ...
Question about Sound- Physics5/17/2007
  Q: Sir, if frequency of two sounds are equal can u say that u r same? i want to know the parameters ...
  A: I'm sorry, I don't understand the first part (can I say that I am same?) 2nd part: If I hear sound1 ...
help plz i need the formula of how its done5/16/2007
  Q: A car decelerates from a speed of 40 km/h to rest in seconds. What is the magnitude of the ...
  A: You first will need the speed converted to m/s. (40 km/hr)*(1 hr/3600 sec)*(1000 m/1 km) = 11.1 m/s ...
battery5/14/2007
  Q: How exactly does an air/saltwater battery work? Where can i find information on it? how can i ...
  A: I have experimented a bit with similar batteries. Without much success. What happens is that you can ...
free falling body5/10/2007
  Q: a.what are the applications of free falling body in Nursing in outline form b.what are the ...
  A: I don't know if I'm going to help you much with either question. a. I'm sorry, I don't know. My ...
mearurement,electricity5/8/2007
  Q: what is difference between chemical and physical balance? is electric current due to flow of ...
  A: >>difference between chemical and physical balance: I'm only guessing here. It might have helped ...
motion5/7/2007
  Q: Im having difficulty in finding final velocities of two masses in a collision. If a car with an ...
  A: In any collision, momentum is conserved. In inelastic collisions, the cars will stick together so ...
not sure5/2/2007
  Q: I am wandering how a led work as a charge indicator in a plug in cigarett lighter flashlight?
  A: All I can do is guess. I haven't taken one apart. I'm going to guess the led is brightest when the ...
motion and acceleration5/1/2007
  Q: the driver of a blue car moving at a speed of 80 km/hr realizes that she is about to rear end car, ...
  A: The question really is that easy, no tricks. If the blue car exactly matches the speed of the red ...
trains in motion4/30/2007
  Q: Two trains , each having a speed of 30 km/hr are headed at each other on the same track. A bird can ...
  A: I assume you accidentally made one typographical error in writing up your question. You said "60/ ...
motion and acceleration4/30/2007
  Q: the driver of a blue car moving at a speed of 80 km/hr realizes that she is about to rear end car, ...
  A: I suspect there's more to the question than what I understand. All I can say about the question ...
radioactivity4/29/2007
  Q: why ionizing power of alpha rays is greater than beta rays?
  A: I'm not the best "expert" to ask this question, but I did find a website ...
inertia4/29/2007
  Q: a MAN FALLING ON CEMENTED FLOOR IS HURT SERIOUSLY THAN A MAN FALLING ON SOFT MUD FLOOR?WHY
  A: There is a saying about falling: "It's not the fall that hurts you, it's the sudden stop." Comparing ...
physics, deriving an equation4/28/2007
  Q: A stretched string, when plucked & then released, gives off a note of frequency 'f' which depends on ...
  A: I'm afraid I'm not familiar with the "method of base units". I tried 2 searches and came up empty. ...
electromegnetism4/26/2007
  Q: what is possiblity when current induced is zero although magnetic field passing through a coil is ...
  A: OK, you didn't like the previous answer? On second thought, I don't like it either. Let me try ...
bifilar pendulum4/26/2007
  Q: Please, I need help with my assessment. WHY and how do the distance between the strings and length ...
  A: I didn't know about this pendulum so I needed to do a search on-line to find information. Apparently ...
electromegnetism4/24/2007
  Q: what is possiblity when current induced is zero although magnetic field passing through a coil is ...
  A: I guess that could happen. The affect of the changes in the 2 parameters would have to cancel out. ...
multimeter4/23/2007
  Q: .. I want to know how the multimeter works...like if we are checking the the transistors to know if ...
  A: I have 3 multimeters in my collection of electronic stuff. One of them is an old analog type. The 2 ...
Ideal Gas Law Related ( I think)4/23/2007
  Q: I am having trouble figuring out how to go about this one. I sure would appreciate some insight. I ...
  A: Yes I think it's Ideal Gas Law Related. And I agree that the advice you were given was good. But I'm ...
SPACE : Ion Engines4/22/2007
  Q: Steve, I read about ion engines/thrusters on wikipedia.They ionise xenon gas and the Xe+ ions are ...
  A: I don't have much specific knowledge about the subject but I'll discuss some of the issues that ...
physics4/22/2007
  Q: If an amusement park ride goes in a constant circle (then the floor drops) does it have a constant ...
  A: I'm quite sure that the ride is required to reach and maintain a particular angular velocity before ...
blackbody radiation4/21/2007
  Q: A blackbody in an enclosure radiates power per unit area sigma*t^4, where t is the blackbody temp, ...
  A: My answer is heavily taken from these 2 webpages: http://en.wikipedia.org/wiki/Blackbody ...
capacitance4/21/2007
  Q: in the derivation of capacitance for parallel plate capacitor,we start like this: C=Q/V. but the ...
  A: I should have remembered from some our previous discussions that you are familiar with Gauss's Law. ...
capacitance4/20/2007
  Q: in the derivation of capacitance for parallel plate capacitor,we start like this: C=Q/V. but the ...
  A: To respond to your first puzzle: My Physics book starts the derivation of capacitance a couple steps ...
motion4/20/2007
  Q: Can you help? A truck with a mass of 2000kg moving up hill at 15m.s requires a force from its wheels ...
  A: OK John, I'll take you through the mechanics of resolving the weight into downslope and normal. ...
Calculating a Vrms Speed for a Gas4/19/2007
  Q: Can you simply check my work and see if I am on the right path. If so, here is theFind the Vrms for ...
  A: Yes, something has gone amiss. In your calculation to obtain temperature you converted from the ...
motion4/19/2007
  Q: Can you help? A truck with a mass of 2000kg moving up hill at 15m.s requires a force from its wheels ...
  A: No mention is made of friction so I guess we assume frictionless. Since the truck is maintaining ...
DC Motor4/18/2007
  Q: Mr. Johnson, Recently in my Physics class, we built a simple brushless DC motor. The project got me ...
  A: Most of what I found and looked at online was from manufacturers describing their units. There are ...
Wedge problem4/18/2007
  Q: I am stumped on a problem for my homework. It involves a wedge, with wheels, and a pulley directly ...
  A: Sorry, I need help understanding the setup. I know it's hard to describe the drawing that you ...
The speed of light4/16/2007
  Q: Will it ever be possible to travel at the speed of light in a space transport vehicle...... ...
  A: 100s of years ago it was said that we would never fly, but who was it that was saying that? Was it ...
Sound/Intensity4/15/2007
  Q: I have some questions about the following situation: Two loudspeakers are located on a coordinate ...
  A: 1. If you go to http://en.wikipedia.org/wiki/Sound_intensity you will see that the intensity of ...
Physics4/15/2007
  Q: I once rode an amusement park ride where riders stand against the inside of a cylinder, once the ...
  A: Newton's 1st says that objects in motion tend to stay in motion, in a straight line, unless acted on ...
plzzzzzzz sir reply me very soon.....4/14/2007
  Q: my questions are: Q1. A stone tied to a string is whirled around. Suppose the string has tension ...
  A: Q1. Work is F*d*cos(theta), the product of force (or tension in this case), times the distance that ...
Lightbulbs/Circuits4/13/2007
  Q: I have a question about lightbulbs and circuits that came up in my physics class the other day: ...
  A: 1) You got the right answer. There are 3 forms of the power equation. We use Ohm's Law to convert ...
Electricity4/13/2007
  Q: I have a question about the following situation: Two identical electric charges +Q are located at ...
  A: Remember that I said "The components Ax and Bx will cancel out at point C"? Because of that, some of ...
gauss' theorem4/12/2007
  Q: i need to clear a few things abt gauss' theorem.let me consider a hemisphere with a charge q at the ...
  A: Yes I agree with what you say on the first part. On the 2nd part, sorry, I'm not sure I ...
Momentum4/12/2007
  Q: I need your help please with the followingA .15 kg frame, when suspended from a coil spring, ...
  A: a) The velocity after a fall of 30 cm is pretty easy. Vf^2 = Vo^2 + 2*a*h where Vo = 0, a=g, and ...
gauss' theorem4/11/2007
  Q: i need to clear a few things abt gauss' theorem.let me consider a hemisphere with a charge q at the ...
  A: Well I agree with most of what you say. I have to disagree when you want to say "cover the ...
Mechanical Waves4/11/2007
  Q: I know this has to be something easy, but for some reason, I just cannot find the right equation or ...
  A: Sorry, I know that I've been slow with my answer. The light string provides the tension to make ...
Electricity4/10/2007
  Q: I have a question about the following situation: Two identical electric charges +Q are located at ...
  A: I agree with almost all of what you did with the first question. Because of the way the question is ...
Electricity/Circuits4/10/2007
  Q: I have some questions about the following circuit: RESISTOR + - __12 ...
  A: I think it might help to start with your>What does the potential at X have to do with anything? How ...
machines4/9/2007
  Q: this s question related to class 2 levers Why is an oar rowing a boat considered as second class ...
  A: You didn't get Kevin, you got the other Johnson. That's OK, my mailman often brings me mail intended ...
Distance travelled of a falling object4/9/2007
  Q: How far must an object fall to reach a speed of 2 meters per second?
  A: I will give you some help finding how to work this. You probably were given 3 or 4 equations of ...
Physics4/8/2007
  Q: A particle of mass 5 kg is acted upon by a force whose power is 10W. If it is initially at rest its ...
  A: If the mass was originally at rest, it originally had zero kinetic energy. So it was given kinetic ...
please satisfy me.4/8/2007
  Q: please detail me the concept of free electrons in a conductor,also when an insulator is charged by ...
  A: The following websites discuss these. They get more detailed in discussion as you go down. ...
plzzzzzzzz answer me very soon....4/6/2007
  Q: questions are Q1. Describe all the forces acting upon a ladder that is leaning against a wall. ...
  A: See followup at the bottom. Q1. The floor is providing an upward force to support most of the ...
power4/6/2007
  Q: who can do more work? A machine of power 1/4 watt of a machime of power 1/2 watt? I just want to ...
  A: Let's say the work to be done is to lift a weight of 10 Newtons 10 meters. A watt is 1 ...
earth's orbit4/5/2007
  Q: Why is the earth's orbit elliptical? That is, what force acts on the earth perpendicular to the ...
  A: There is no force that acts on the earth perpendicular to the force of the sun. (At least nothing ...
Earthing a simple circuit4/5/2007
  Q: Consider a simple circuit having, a cell and a bulb connected by UNINSULATED wires? If any ONE point ...
  A: If I understand right, the circuit involves 2 uninsulated wires (one from cell + to one side of the ...
brownian motion4/4/2007
  Q: i want to ask questions related to brownian motion 1) why does brownian motion of the suspended ...
  A: Let me set up an analogy. A small classroom, with no furniture but one teacher and 20 6 year old ...
Physics4/2/2007
  Q: Can you please sxplain to me what the differences between gravity ahd magnetism are? You'd be a big ...
  A: There are some similarities. They can both exert force. Our earth is a source of both. These ...
Newtons's Third Law4/1/2007
  Q: When an object rests on a table, it exerts a force on the table and the table exerts an equal and ...
  A: Do you mean during the time the object is still accelerating up to its terminal velocity? I'll ...
mechanics3/30/2007
  Q: it's a problem and here is thethere is a movable wedge(mass 4kg) at an angle of 30.the lower vertex ...
  A: OK, I see the setup, thanks. I agree that the force that will accelerate the 1kg mass with respect ...
egg cracking3/30/2007
  Q: what is the pressure required to crack an egg (by tapping it on the edge of some thing)or the ...
  A: Sorry, there's no table I can look that up in. The answer would vary depending on the orientation of ...
general science3/29/2007
  Q: the phrase "ten meters per second squared" describes the
  A: Those are the units of acceleration. To describe what it means: assume an object starts with an ...
Newtons's Third Law3/28/2007
  Q: When an object rests on a table, it exerts a force on the table and the table exerts an equal and ...
  A: Newton's Third Law does apply. There are actually several forces involved while the object is ...
Motion3/28/2007
  Q: A hollow cylinder of mass M and a radius R rolls down an inclined plane. A block of mass M slides ...
  A: I will use the conservation of energy principle. Potential energy, M*g*h, will be converted to other ...
inertia3/27/2007
  Q: A 60 kg skater begins a spin with an angular speed of 6 rad/s, by changing the position of her arms, ...
  A: Her angular momentum is conserved and is calculated as I*w. You might wonder if energy is ...
Tangential Speed3/26/2007
  Q: What is the tangential speed of Nairobi Kenya, a city near the equator. The earth makes one ...
  A: One way to figure this is to calculate the circumference. Then figuring that the earth does one of ...
Satellite3/26/2007
  Q: An artificial satellite in a circular orbit around the Sun has a period of 8 years. Determine the ...
  A: OK. I guess I can walk you through the rest of the steps - but it worries me. If you were given this ...
acceleration3/25/2007
  Q: A train passes through a town with a constant speed of 16 m/s. After leaving the town, the train ...
  A: You were probably given a set 3 or 4 of equations to use on problems like this. The way to choose ...
Satellite3/24/2007
  Q: An artificial satellite in a circular orbit around the Sun has a period of 8 years. Determine the ...
  A: Any particle moving in a circular path requires centripetal force, Fc, of Fc = m*v^2/r to keep it ...
Displacement Vector3/23/2007
  Q: The x and y components of a displacement vector are -3.00 m and +4.00 m, respectively. What angle ...
  A: Let me help you drawn this out. Draw an x-y coordinate system. Preferably on graph paper. Just let ...
velocity,distance,time, acceleration3/23/2007
  Q: okay so here's theThe easter bunny runs along a straight and narrow path with a constant speed of ...
  A: During those 2.3 hours, the tortoise was slowly increasing his speed. Meanwhile the rabbit was ...
Let's say a giant who had a mass equivalent to one quarter of the earth's mass ....3/22/2007
  Q: Let's say a giant who had a mass equivalent to one quarter of the earth's mass jumped off the earth. ...
  A: This can be approached various ways. By the principle of conservation of momentum. If the giant ...
physics problem(hoping for exact answers)3/22/2007
  Q: 1. while giving birth, a mother's uterus contracts and exerts a sudden force of 40 N on the baby ...
  A: My practice is to avoid just giving answers to problems. My favorite questions ask for an ...
physics problem(hoping for exact answers)3/21/2007
  Q: 1. while giving birth, a mother's uterus contracts and exerts a sudden force of 40 N on the baby ...
  A: 1. The net force is (40 - 39.8) N. Mass is 2.7 kg. Fnet = m*a s = (1/2)*a*t^2 2. The force on the ...
physics3/20/2007
  Q: Where does a tennis ball bounce higher on top of a mountain or on a plain at sea level?
  A: If the collision of the ball and the ground were perfectly elastic, and if this happened in a ...
fuse3/19/2007
  Q: an electric kettle is rated 3kW,250V. so its current carrying capacity is 12A. can it be used in a ...
  A: ***Follow-up: I re-read my answer, and I'm embarrased. I must have read your question wrong and ...
Flux3/18/2007
  Q: Why is it that when working out the flux through a coil of wire (using flux = BA), we calculate the ...
  A: It looks like you're not clear on the definitions of field and flux. It's tricky. When you say "most ...
FORCE3/18/2007
  Q: An object lying on a horizontal surface is tied with a rope at one end. The object starts moving ...
  A: Look at all forces that are in effect. There are at least 3, generally 4 (if you count the tension ...
receivers3/17/2007
  Q: What do the terms homodyne receiver, heterodyne receiver, intradyne receiver stand for? (please ...
  A: I'm sorry to admit I can't define them either, so I found links to various discussions. Here are ...
Flux3/16/2007
  Q: Why is it that when working out the flux through a coil of wire (using flux = BA), we calculate the ...
  A: I'm not clear what you mean by the terms loop versus coil. Apparently they are separate circular ...
Newton's Law of Gravitation...3/15/2007
  Q: Can you see if I am doing this correctly? The question is: Calculate the energy in joules ...
  A: I expected the cost to come out higher too, but your work looks almost perfect. I disagree with the ...
Rate of heat flow3/13/2007
  Q: The rate of heat energy flow along a metal bar at any point is proportional to the temperature ...
  A: Calculate T(0) and T(1). Plugging 0 and 1 in for x, T(0) = 1/10 = 0.1 T(1) = 1/12 = 0.083 T(2) = ...
Terminal speed in fluid3/10/2007
  Q: A spherical object of radius (r) moving slowly in a fluid medium is subject to a viscus drag force k ...
  A: There are 3 forces acting on the ball bearing: Weight of the ball bearing W = m*g Bouyancy, B, of ...
Forces3/8/2007
  Q: m1 m2 F--- |__||---| surface under m2 in frictionless ...
  A: The first problem is that m1 must be pressed against m2 hard enough to keep it from falling. The ...
Earth's Spin (and moment of Intertia, I)3/8/2007
  Q: The moment of inertia of the eart about its spin axis is approcimately 8.03 x 10^37 kg m^2. (a) ...
  A: The moment of inertia, I, is a term that is defined as the sum, for all particles of a body, of the ...
physics problem3/7/2007
  Q: 1. a man weighing 160 lb stands in an elevator. as the car starts upward, for a short time there is ...
  A: 1a. If the man accelerates, there is a net force on him. First, need an expression for his mass: w = ...
themordynamics3/5/2007
  Q: A jogger's internal energy changes because he performs 6.20* 10^5 J of work and gives off 4.9*10^5 ...
  A: Oh C.C. I'm sorry, I messed up. I used 4.9*10^5 J for both Q and W. Revised reply: The jogger's ...
thermodynamics3/4/2007
  Q: I have to fill out a chart with deltaU, Q, and W I have fill out most of it but can't figure out how ...
  A: C., I found what seems to be a problem with the table you gave me to work with. I'll let you see ...
themordynamics3/4/2007
  Q: A jogger's internal energy changes because he performs 6.20 105 J of work and gives off 4.9 105 J ...
  A: C., I think you mean 6.20 105 J to equal 620,000 J. If so, to avoid confusing me, I would like you ...
Physics applying to the car3/2/2007
  Q: I am wondering how Newton's three laws apply to the car? Thank you so much, Ash
  A: Newton's 1st: If the car is sitting at a red light, when the light turns green, the driver needs to ...
Electrocution3/1/2007
  Q: my question is somewhat longer ,sorry for it imagine theres a high voltage power line suddenly ...
  A: 1) That line may jump around on the ground. Sparks may also fly. If you are far enough away to avoid ...
Problem3/1/2007
  Q: I was wondering if you can go through the steps and eplain how to solve this problem. A rock ...
  A: a) Work is calculated as the force exerted times the displacement the force caused -- times ...
Rate of speed2/28/2007
  Q: After traveling 110 miles of a 200 mile trip a motorist decreased his speed by 20 mph for the last ...
  A: Let the total time be T, the time of the 1st leg be t1 and time of the 2nd leg be t2. So T = t1 + ...
circular motion2/27/2007
  Q: IN A CIRCULAR, THE DIAMETER OF GLOBE OF DEATH IS 20M FROM WHAT HEIGHT MUST A CYCLIST START IN ORDER ...
  A: I haven't seen this done. I searched and saw a bunch of photos, but I still don't know for sure how ...
the egg..2/25/2007
  Q: how much force is needed to break an egg? because we are about to make a footwear that could walk on ...
  A: It's hard to say how much force is needed to break an egg. It would depend how you deliver the ...
physics2/24/2007
  Q: joyce here again...,asking for your help...pls.Our topic is all about potential and kinetic energy. ...
  A: 1. Potential energy = m*g*h. You have the mass, g=9.8 m/s^2, h = # steps * height/step. (Convert cm ...
Conservation of Momentum (Inelastic Collisions)2/23/2007
  Q: Yes, we have the initial velocity of the ball of 1.3 m/sec. We have the sliding distance of ...
  A: OK, ummm, I would like to modify what I said in my first answer. A little embarrassing - I just came ...
Conservation of Momentum (Inelastic Collisions)2/22/2007
  Q: I think I have this problem figured out, but there is a tiny roadblock in my progress. If a ball ...
  A: If I understand the problem right, I think it's more of a conservation of energy problem. Do you ...
Electric Fields2/8/2007
  Q: I am really struggling with the concept of electrical forces and fields. My question is: A particle ...
  A: Don't worry about the description being lengthy. It helps me to know where the confusion lies. ...
density2/8/2007
  Q: The question gives me the weight of the block of gold in newtons is it still possible to figure this ...
  A: I can't tell where you're hung up, so I'll work it out with the assumption I made before, that the ...
physics2/7/2007
  Q: It is said that thicker conducting wires offer less resistance to curren. But i fail to understand ...
  A: If each of 2 different size copper wires is carrying 1 amp, the thicker wire has less resistance. ...
physics question2/7/2007
  Q: The mass of a newborn baby’s brain has been found to increase by about 1.0 mg per minute. How much ...
  A: Interesting information. I wonder how they determined that. Anyway - well first you need to find ...
density2/6/2007
  Q: I have a question about finding the weight if an object in water. I have the weight of the gold gold ...
  A: This is a fairly easy one to explain. You haven't given me the dimensions or the volume of the ...
Projectile motion2/1/2007
  Q: where do you find the coefficient of drag in an example pertaining to a bullets flight?
  A: It looks like these web sites will tell you all about that, and more. ...
Gauss's Law1/31/2007
  Q: I have a (three-part) question on Gauss’s Law. If you enclose a dipole in a spherical Gaussian ...
  A: What Gauss’s Law says in the case you describe is that the NET flux through the surface would be ...
home made wind generator1/30/2007
  Q: I am trying find a way to make a simple (but powerful) alternating generator of electricity from a ...
  A: The squirrel cage motor is an induction motor. The rotating magnetic field generated by the stator ...
life period of aircraft1/30/2007
  Q: how long do aircraft last, I mean in flying terms, can a plane built 20 years ago still flyable?
  A: Check out these sites: http://edition.cnn.com/TRANSCRIPTS/0006/24/stc.00.html Go about 2/3 of the ...
Electric motor amps1/28/2007
  Q: Is there an equation to determine max amps for a 440 VAC motor rated at 15 HP?
  A: Well, ummm ... yes, but. There are more factors invlolved than what you list. I'll discuss the ...
3 pin plugs1/26/2007
  Q: what are the safety features for a 3 pin plug?
  A: My answer is a brief description of the way power is distributed in the US. I'm not sure how similar ...
Volume1/24/2007
  Q: A small sculpture made of brass ( p brass = 8870 kg/m^3 ) is believed to have a secret central ...
  A: The decrease in weight is due to buoyancy. The amount of the decrease (1.90 N), and the density of ...
physics1/23/2007
  Q: Our new topic is all about free falling bodies, and our teacher didn't explain it well again and ...
  A: There is a series of motion equations that you probably have been given in class. Sometimes not all ...
LED LIGHT RUN..... I NEED HELP!1/23/2007
  Q: I thought I knew enough about electricity and physics to do an LED light project.... I WAS WRONG. ...
  A: I admire your confidence that you can figure it out, with a bit of help if needed. My first concern ...
Physics1/21/2007
  Q: A Toy rocket launched from the ground rises vertically with an acceleration of 33m/s2 for 2.8s until ...
  A: You can use this basic motion equation to get the velocity after the powered phase of the flight: V ...
physics question1/19/2007
  Q: When the space shuttle is in flight, and it discharges it's booster rockets, the space shuttle ...
  A: I worked on it for 8-9 years and thinking about it again was a pleasant trip down memory lane. My ...
temperatures1/18/2007
  Q: Which would cause a more serious burn, 30g of steam or 30g of liquid water, both at 100 degrees C ...
  A: That's hard to answer but I'll give it my best guess. It's true that the steam has more heat ...
HEIGHT CALCULATION1/18/2007
  Q: STONE OF MASS 0.62KG FIRED UPWARDS AT ANGLE TO GROUND, SPEED 5.5M/S. KE AT MAXIMUM HEIGHT ABOVE ...
  A: At max height, there is no vertical component of velocity. So the KE at max height can tell you the ...
controling gravity1/17/2007
  Q: could we control gravity
  A: No we can't, at least not with any knowledge we have now. The force of gravitational attraction, F, ...
Simple Harmonic Motion1/17/2007
  Q: A 0.350 kg block moving vertically upward collides with a light vertical spring and compresses it ...
  A: You seem to be off by a factor of 2. I started out guessing that you messed up by not using the ...
Heat1/16/2007
  Q: Two spheres labled A & B, have identical masses, but are made of different substances. The specific ...
  A: OK - an amount of heat, Q, is given to both. We don't know the mass, so I say m is the mass of both. ...
Perpetual energy machine1/16/2007
  Q: Is it possible to make a machine that feeds off the energy it creates? Like a lamp shining on a ...
  A: Sorry, no. The example you describe would fail. An incandescent light is only about 5% efficient at ...
Mass1/14/2007
  Q: A force of 250N is applied to a hydraulic jack piston that is 0.01m in diameter. If the piston which ...
  A: Problems with hydraulic jacks can be solved fairly easily once you understand pressure. Pressure is ...
i can hardly understood this, pls. help me1/13/2007
  Q: But honestly, i dont know how to apply the given from those equations. Can you pls. show me the ...
  A: Sorry that didn't do it for you. OK, with bells and whistles and 3-part harmony: 1)A car moves at ...
i can hardly understood this, pls. help me1/12/2007
  Q: sir steve! Hope your doing fine as always. i need help again. Im kinda confused what equation would ...
  A: 1) The equation that will work well on this is x = Vo*t + (1/2)*a*t^2 where Vo is the original ...
Pressure1/11/2007
  Q: An ice cube, p = 917 kg/m^3, is sliding down a frictionless incline of 16 degrees. The sides of the ...
  A: The 917 kg/m^3 seems to be density (you call it p?). The volume of the cube is .75^3 m^3. So the ...
Physics1/11/2007
  Q: Good mornign sir!, I am not that good in Physics but I must pass my Physics subject. May I ask your ...
  A: The waves have a speed of 0.32m/s. So how far does a particular crest go in 1.6 s? 0.32 m/s * 1.6 s ...
egg drop experiment1/9/2007
  Q: Dom's mom here - I'm trying to help Dominic understand physics concepts - gravity, air ...
  A: >Would Newton's 2nd law have anything to do with the parachute drop? Yes it would. This explanation ...
Gun Recoil1/9/2007
  Q: A rifle weighs 50.0 N and its barrel is 0.750 m long. It shoots a 25.0-gram bullet, which leaves the ...
  A: We will need the time, t, that the bullet was still in the barrel. Using the equation x = ...
AC motors1/8/2007
  Q: I’m having trouble understanding the principles of operation of a single phase AC motor. I ...
  A: It seems that you're mistaken about your statement: "there should be a constantly rotating magnetic ...
egg drop experiment1/8/2007
  Q: This is my first science experiment. I dropped medium and extra large eggs, raw and hard boiled from ...
  A: It depends on how the parachute was designed. I assume there were 4 12 inches strings, one to each ...
force problem1/7/2007
  Q: The problem is that there are 2 blocks connected by a string (that has the same mass everywhere in ...
  A: I agree with your answer for 2). The midpoint of the rope will accelerate the same as all the other ...
i can hardly understood this, pls. help me1/5/2007
  Q: its me and needs a little (big) help again! to open up, i would like to greet you a happy prosperous ...
  A: you have a good one too. And I should ask you, for a new question unrelated to an old one, don't ...
i need help so bad!!1/5/2007
  Q: your teacher tosses a basketball and it goes through the hoop! how long does it take the ballto ...
  A: My first thought is that there is much more data given than is necessary. Example: The horizontal ...
Spring constant12/31/2006
  Q: A ping pong ball weighs 2.5 * 10^-2N. The ball is places inside a cup that sits on top of a verticle ...
  A: The spring accelerates the ball while the spring returns to its rest position, releasing its stored ...
impulse &acceleration12/30/2006
  Q: Dose a moving have impulse? Please give reason also. A car is accelerating at the road which force ...
  A: I don't clearly understand your question so I'll explain about impulse as well as I can. It's very ...
Mass12/30/2006
  Q: A cable stretches by an amount d when it supports a crate of mass M. The cable is replaced by ...
  A: I refer you to http://en.wikipedia.org/wiki/Young's_modulus. About 1/2way down the page is the ...
newtons laws of motion12/28/2006
  Q: A block of mass m is placed on top of an inclined plane. The mass of inclined plane is M. All the ...
  A: Assumptions: The inclined plane appears, when observed from the side, to be the hypotenuse of a ...
friction12/28/2006
  Q: What is difference between 'sliding' 'rolling' 'slipping' of a body when friction is considered ? ...
  A: I find that in many contexts, slipping and sliding are used as synonyms. But in a relatively new ...
spheres12/25/2006
  Q: A solid sphere of radius R rotates about a diameter with an angular speed. The sphere then collapses ...
  A: The "internal forces" would have done work in collapsing the radius, so we won't think about ...
help plz12/21/2006
  Q: the answer which u gave explained it very well and i did understand it. but the only prob is tht ...
  A: So the book is talking about a condition where only the ice above the surface melted and the ice ...
Kinetic Energy12/20/2006
  Q: A 50 kg rider on a moped of mass 75 kg is traveling with a speed of 20 m/s. Each of the two wheels ...
  A: Yes, it looks like your formulas are good. So here's some help with converting 20 m/s to rad/s. When ...
physical science12/20/2006
  Q: if it took 5 seconds to lift the crate using a machine what wat the rating of the machine
  A: I think power is the rating you are looking for. In lifting the crate, the machine does work, W. W = ...
Thermal Energy12/17/2006
  Q: Johnson, I'm reviewing for my physics final and I'm having a little trouble with this problem. ...
  A: From conservation of energy, the potential energy of the shot when on top of the building needs to ...
help plz12/17/2006
  Q: thnks for ur mail. can u plz help me out with this question? when a floating piece of ice melts into ...
  A: Medicine is a fine place for someone with science talent. Go for it. Ice floats because it is less ...
Archimedes principle12/15/2006
  Q: Please answer this, Why wouldn't the weight of the fish have an apparent decrease due to the ...
  A: (followup below) I think I can convince you with an analogy. Say you were standing on a bathroom ...
Archimedes principle12/14/2006
  Q: Please help me with this question Steve. A bucket containing water is placed on a compression ...
  A: Let the fish's weight be W2 Kgf (whatever a Kgf is). The balance will show W1+W2 Kgf. Archemedes ...
Work12/14/2006
  Q: i am a grade 12 physics student, and i have a question regarding work done when an object is lifted ...
  A: It seems so doesn't it? If you did that with several heavy objects you would 'work' up a sweat. But ...
field force12/11/2006
  Q: 1. what is voltage, are there positive charges involved here? how does this work? 2. where does the ...
  A: 1. Starting with the charges, there are positive and negative charges. This is one of the origins of ...
linear momentum12/10/2006
  Q: could u help me with this question A man of mass "M" having a bag of mass "m" slips from the roof ...
  A: I can help with that but I'm going to leave most of the algebra to you. You need to know how much ...
Kinematics12/10/2006
  Q: During the spin dry cycle of a washing machine, the motor slows from 95 rad/s to 30 rad/s while ...
  A: The familiar 4 formulas of linear motion have equivalents in rotational motion V = Vo + a*t ...
relative motion12/9/2006
  Q: What one measurement will two observers in relative motion always agree upon? Please help!
  A: I'm not 100% sure this is what you need. My answer is the measurement of the relative motion between ...
Physics12/8/2006
  Q: 1. If one body is positively charged and another body is negatively charged, free electrons tend to ...
  A: Given such a long list of questions, I'm not willing to go to much work on any that I don't know ...
atoms of air12/8/2006
  Q: sir, air molecules are alwalys surrounding us.they are made of mass though negligible.then why ...
  A: The air molecules do have an effect (but it's not their weight), it's a slight amount of bouyancy. ...
Heat12/7/2006
  Q: Could you please check my answers to see if they are right THANKS 1. A silver bar 0.125 meter ...
  A: Given such a long list of questions, I'm not willing to go to much work on any that I don't know ...
what determines current in a lemon battery?12/6/2006
  Q: i'm a secondary school physics teacher. i made a lemon battery by connection about 24 lemons in ...
  A: I'm glad that you asked several of us. I can confirm that I've seen those results from my own ...
Where does the springs energy go?12/6/2006
  Q: A spring made of metal is compressed and while keeping it compressed (by some apparatus)it is put ...
  A: This is a fascinating question. I thought the energy had to show up as heat, but I wasn't sure, so I ...
linear momentum12/5/2006
  Q: can u help me out with this question. Two persons each of mass m are standing at the two extremes of ...
  A: I assume "resting" means it is stationary - wouldn't want anyone to get run over. I need to make ...
help12/4/2006
  Q: A swimmer is under water and looking up at the surface. If someone holds a coin in the air, above ...
  A: First have to assume the swimmer can remain perfectly still and there's nothing else causing ...
physics help12/4/2006
  Q: Light of wavelength 550nm is incident on a diffraction grating. If the third order bright fringe is ...
  A: Optics was never my interest and I forgot most or all of what I learned. So I had to turn to the ...
Inductor Charging12/3/2006
  Q: Does an inductor charge faster through a low resistance or a high resistance? and why? I know an ...
  A: When a voltage, E, is applied (for instance by closing a switch) across a series R and L, the ...
Physics question12/2/2006
  Q: You observe three (non-interacting) particles with: m1=1 kg, m2 =2 kg, and m3 =3 kg, and at ...
  A: Unfortunately I can't read your question. Example: It looked very bizarre (&s and #s) in my email ...
Tennis Ball Momentum11/30/2006
  Q: But where does the wall's momentum come from(since the earth rotates?) and does the wall's momentum ...
  A: Sorry my previous answer didn't do the job. >But where does the wall's momentum come from(since ...
Tennis Ball Momentum11/29/2006
  Q: A tennis ball bounces off a wall elastically. How does wall have momentum -2mv to transfer, but no ...
  A: Saying that a tennis ball bouncing off a wall is elastic, is an approximation. KE is not 100% ...
kinetic energy11/28/2006
  Q: I want to desing a cell phone battery that depends on kinetic energy. How can I send the amount of ...
  A: Hola Jorge, I think I need more detail to answer fully. There are flashlights (flashlights in ...
Pole Vaulting11/28/2006
  Q: How is it possible for a pole vaulter's center of gravity to pass beneath the bar?
  A: Consider that you made a large U out of cardboard. The c of g would be someplace in the open area ...
Har,onic oscillator11/27/2006
  Q: I have a simple question, what is the angular frequency in the following equation? x = (20.6 cm) ...
  A: So you need to convert to the form x = A*cos(w*t + p) where w is omega, in radians/second, and p ...
Solar Cells11/26/2006
  Q: I want to know about Solar Cells.Could you help me to find some general information about Solar ...
  A: These links will probably give you more than you need to know. I hope one of them will be just ...
Accleration11/26/2006
  Q: I understand the formula for finding acceleration and that the SI unit for acceleration is meters ...
  A: Let me start with a review of velocity. Velocity, V, is the rate of changing position. V = delta ...
Is it possible to send Messages Backward in Time by using Tachyons ?11/23/2006
  Q: My question would be about Tachyons. It is stated that, because of their superluminal speeds, (v > ...
  A: Unfortunately my physics expertise is minimal beyond the first year of college physics. This topic ...
White laser11/21/2006
  Q: Is there anyway for there to be a white laser? Maybe bouncing a red, green, and blue laser off of a ...
  A: If you and 2 friends each had a laser pointer, one each red, green, and blue, and could hit the same ...
General College Physics11/21/2006
  Q: Is water a conductor or insulator. Explain?
  A: Heat conductivity: The material with the highest heat conductivity listed by my source is purified ...
Physics Question11/20/2006
  Q: A 0.6m-diameter lead sphere has a mass of 5600 kg. A dust particle rests on the surface off the ...
  A: The normal everyday weight of the dust particle in the earth's gravitational acceleration is given ...
Phaser on stun - energy gun calculation11/18/2006
  Q: Greetings. I would really appreciate the help with my sons problem . . . which I happily volunteered ...
  A: Well if that's all the given information, I'm kind of stunned too. I guess the student is required ...
circuits11/18/2006
  Q: It is easy to see that a sinusoidal voltage applied directly to the terminals of a passive component ...
  A: OK Mark, I maintain that an individual component buried deep in the circuit will have a potential ...
circuits11/16/2006
  Q: In my circuits class, we were first taught how to solve DC circuits. Then we moved on to AC ...
  A: Well, the 2 premises are not true for arbitrary circuits of any complexity or size. For example, the ...
Physics11/16/2006
  Q: Johnny drives to wisconsin (1920 miles) in 32 hours. He returns hoem by the same route in the same ...
  A: a) The units of speed, normally used for car travel (in the US), is miles per hour or miles/hour. ...
Laser frequency11/15/2006
  Q: I have a green and red laser pointer, and was wondering if there is an inexpensive way to create a ...
  A: I answered without learning all the details. Thanks for getting me to learn more. Knowledge is good. ...
Laser frequency11/14/2006
  Q: I have a green and red laser pointer, and was wondering if there is an inexpensive way to create a ...
  A: Sorry no, that's not going to work. The light from a laser is a specific frequency. A filter can't ...
physics help11/13/2006
  Q: An electron having a speed of 4*10^6 m/s is moving perpendicular to a uniform magnetic field of 0.5 ...
  A: The force F (a vector) on a charge q moving in a magnetic field B is given by F = q*(vxB), where ...
rocket height.11/13/2006
  Q: Got a question here that I dont really know how to tackle. A net force (F= -mg - kv^2 ) acts during ...
  A: To be sure I understand: * The net force after engine cutoff is F = -mg - kv^2. * You're asked to ...
radio waves11/8/2006
  Q: i'm a 32 years old teacher. will you please tell me why the dishes to receive satellite tv signals ...
  A: I've had a similar question before and it is frustrating how little there is to be found on the web ...
Question on acceleration11/8/2006
  Q: a 2.0kg otter starts from rest at the top of a muddy incline 85cm long and slides down to the bottom ...
  A: 2 equations will do this for you. The otter starts from rest at the top, accelerates for 0.5 seconds ...
School Physics11/7/2006
  Q: The definition of Equilibrium I have is : When a body does not change its state of rest or uniform ...
  A: Your definition is OK. The problem is in your understanding of it. Perhaps the definition in my old ...
physics11/7/2006
  Q: what is the done by the earth in moving around the sun?
  A: The rotation of the various planets would set up an equivalent to our tides. Because of the heat, ...
physics question11/6/2006
  Q: not sure if you are the right expert? I want to know if disc magnets threaded onto a live ...
  A: I'm not sure I'm the right expert either. I did some searches for disc magnets. One problem I see is ...
air pressure11/6/2006
  Q: I would like to know how the weather is affected by air pressure? I'm on the first year of faculty ...
  A: Well I know that when we have a high pressure system overhead the weather is nice. When there is a ...
spontaneous combustion ?11/4/2006
  Q: Whenever I have a tree trimming service deliver a pile of fresh cut mulch (green) it burns and ...
  A: This is more a question for a biologist, but I can take a shot at it. It's decomposition at work. ...
Rigid Body11/4/2006
  Q: A rigid body rotates about a fixed axis with a constant angular acceleration, does the tangential ...
  A: Yes. Tangential means perpendicular to a radius. Let's talk about velocity first. Velocity in the ...
physics11/3/2006
  Q: if a fish is resting on the bottom of a bucket that is filled with water while it is being weighed ...
  A: No it will not. A similar and common question regards a truck full of canaries. And that is a bit ...
DC to AC11/3/2006
  Q: What is the specific terminology used for the conversion of DC to AC?(Like the conversion of AC to ...
  A: The usual device to do this is called an inverter. See http://en.wikipedia.org/wiki/Inverter This ...
walking11/2/2006
  Q: I am a high school physics student with a question. What are the forces involved in walking? Also, ...
  A: In the normal stride, there's not much more than picking up your foot at the end of its contact with ...
PHYSICS11/1/2006
  Q: what do you mean by degree of freedom of system in general?
  A: It's hard to answer in general. There are specific meanings depending on the field you are in at the ...
Rotational Inertia10/31/2006
  Q: Johnson, Thanks for answering so quick! I drew a diagram and uploaded it here; ...
  A: My answers are sometimes difficult without a figure so I will probably include a link thru tinypic ...
heat10/31/2006
  Q: If you wish to warm 100 kg of water by 22°C for your bath, how much heat is required? ((The heat ...
  A: I have to point out how easy this is - if you understand. Perhaps I can help you understand - that ...
Rotational Inertia10/30/2006
  Q: Johnson, Hi there! I was wondering if you can help me with this problem i have to solve. I've tried ...
  A: I'm afraid I need to ask for more detail. I need a clear picture in my head of the parts. Are the 2 ...
conservation of momentum10/29/2006
  Q: Could u please help me with this question-An open watertight railway wagon of mass 5000 kg is moving ...
  A: This is a case of conservation of momentum in an inelastic collision. Inelastic because the rain ...
calculating useful energy output10/29/2006
  Q: In a lab excercise where a 1.1 kg sample of water with an initial temperature of 12 degrees celcius ...
  A: You're right, Q=mct is the answer. That will give you calories. I guess that's the "useful" energy ...
physic10/28/2006
  Q: I would appreciate your answering to these questions. The production of carbon dioxide increases as ...
  A: This is a question better asked of a biologist but I can offer an opinion for #1. Many, or perhaps ...
I was in a recent car accident.10/27/2006
  Q: I was in a recent automobile accident in which I was ejected from the car. We were traveling at ...
  A: You are either a miracle or a prankster. I'll believe you're a miracle. But there's no way to know ...
sound10/25/2006
  Q: I actually have more than one question if you dont mind answering then i would greatly appreciate ...
  A: 1) That particle will be disturbed very little. 2) I'm not very sure on this one but I'd guess A ...
Defect in Newton's Law of Motion.. !10/24/2006
  Q: Q) If we throw a ball up it comes down .. Action and Reaction Newton's 3rd Law... Ball goes up ...
  A: Well I'm going to try to defend my friend Isaac. >If we throw a ball up it comes down .. Action and ...
rotational equilibrium10/23/2006
  Q: I just want to ask how am i going to solve a see-saw problem with two masses at one end and a single ...
  A: I think you left out a word in the sentence about the unknown. But I can describe in general how to ...
calucalting the force of an ocean wave10/22/2006
  Q: Can we use Newton's 2nd Law -- F=MA -- to describe the force of an ocean wave hitting a sea wall? ...
  A: Waves are classified as transverse (particles vibrate perpendicular to the direction of wave travel) ...
belt tension gauge10/22/2006
  Q: Please give me the equations. How does the tool know the angle between the forces?how does a belt ...
  A: Sorry it's taken a couple days to answer. I have been thinking about how best to describe this, and ...
belt tension gauge10/21/2006
  Q: how does a belt tension gauge measure tension from a perpendicular force? is there some spring or ...
  A: There seem to be some contradictions in the literature from the link you gave. Maybe you saw that ...
Gun Recoil10/21/2006
  Q: A 30-06 caliber hunting rifle fires a bullet of mass 0.00953 kg with a velocity of 500 m/s to the ...
  A: Before pulling the trigger, the momentum of the rifle (m1) including the bullet (m2), is (m1+m2)*0 ...
pull and push10/19/2006
  Q: why is it easier to pull than to push. Explain it with vectorical reasons
  A: I don't believe it's always true. Sometimes it's easier to push than pull. What if you had a tall ...
PHYSICS10/15/2006
  Q: why in metals relaxation time is equal to collision time?
  A: This topic requires detailed discussion. I refer you to the following sites. ...
incline10/14/2006
  Q: A 9.0kg box slides from rest down a frictionless incline from a height of 5.0m. What is its speed at ...
  A: This is a question that will benefit from use of the principle of conservation of energy. When at ...
light10/11/2006
  Q: Say you are in space, how can you recognize a double star (2 stars that revolve around their center ...
  A: The site http://en.wikipedia.org/?title=Double_star gave me a link to ...
physics (velocity/distance traveled)10/10/2006
  Q: I need help finding the formula that will solve this problem: A ball is thrown horizontally from a ...
  A: I'm going to assume the ball is "thrown", not from shoulder height but from the top surface of the ...
equilbrium10/10/2006
  Q: A body is in translational equilibrium if it is either at rest or moving with constant velocity, is ...
  A: According to the Encyclopedia Britannica: "equilibrium is a condition in which the net force acting ...
energy question10/8/2006
  Q: I've been stuck on this question and many others. I don't know how to answer it. "a daredevil on a ...
  A: Let me give you a tip. The 35 m/s speed is at the angle of the ramp - I know, you don't know the ...
magnitude10/8/2006
  Q: I am sorry about the confusing question. Fm = the magnitude of the gravitational force on the marble ...
  A: Newton's law of universal gravitation says the force between any 2 mass particles, mass m1 and m2, ...
Energy used by Light Bulbs10/5/2006
  Q: How much does it cost to leave a 100w light bulb on for a year? Assume average current cost for one ...
  A: According to http://www.coaleducation.org/Ky_Coal_Facts/electricity/average_cost.htm, the average ...
Sound/motion10/4/2006
  Q: We are researching motion for our grammar class, and I am writting my paper on golf. Why a golf ...
  A: I've never had a golf ball go flying past my head (fortunately) so I'm not sure I've heard the sound ...
projectiles10/4/2006
  Q: A Basketball player has to put the ball into a hoop 3.7meters above the court. If the player ...
  A: First you need to determine the horizontal and vertical components, Vho and Vvo, of the original ...
potential difference relating to electric fields10/3/2006
  Q: A cell (source of emf) has a voltage across the two terminals because the cell causes electrons to ...
  A: Regarding your last paragraph, about Kirchoff: yes the electrons pass through. It's like water ...
Dynamics10/2/2006
  Q: oopz..i messd up a bit vid da ques.heres da ques: - two shipz A and B leave the port at the same ...
  A: This is really just an exercize in trig. In 1 hour A goes 15 km and B goes 10 km. Draw it out on ...
VERY VERY URGENT ?????????10/1/2006
  Q: (SENDING IT AGAIN) hi i'm in 12th, please give me proof of parallel axis theorem(rotational ...
  A: OK, I'll try to help. I notice that the web sites I gave you had an un-needed complication in one ...
What would we see, if we could travel at the speed of Light ?10/1/2006
  Q: My question is about travelling at the speed of light. If I could travel exact at the speed of ...
  A: I follow the question archive fairly closely and have enjoyed seeing some of your questions. They ...
Projectile motion9/25/2006
  Q: A fire hose held near the ground shoots water at a speed of 5.1 m/ s. At what 2 angles could the ...
  A: It's interesting. I had an almost identical question 10 days ago. I hope it's OK with you if I just ...
fluid dynamics?9/23/2006
  Q: If a circular vessel containing water spins slowly, how is the water inside generally affected? ...
  A: When the vessel is first brought up to the slow speed, the rotation of the water will lag behind for ...
VERY VERY URGENT ?????????9/22/2006
  Q: please give me proof of parallel axis theorem(rotational motion)&explain thoroughly. Why integral in ...
  A: see followup at end Giving you links to some good discussion will be quicker than me writing up ...
football9/22/2006
  Q: This is a physics question about football. Since I am not familiar with American football, I have ...
  A: The stuff about football is just trying to make it hard to find the critical info. And it would be ...
laser9/20/2006
  Q: would cds made for red lasers be readable by blue laser machines ?
  A: Yes and no, or maybe. Check out ...
Newtonian Physics: Gravity9/19/2006
  Q: How strongly, and in what direction does a 1-newton apple pull on the earth? I understand that the ...
  A: The apple exerts a 1-Newton pull on the Earth - toward the apple. It's fitting that we're talking ...
Science Fair Project Research9/19/2006
  Q: How far can you throw a water balloon before it will bust? This is my science fair question. I am ...
  A: This should be a fun project. I'll try to help you do some proper research while you have fun. One ...
projectile motion9/15/2006
  Q: i'm not familiar with the formulas u used. the ones i learned were: vf = vo + at final velocity = ...
  A: I did use the first of the 2 formulas you listed above. But I changed a few variable names to ...
projectile motion9/14/2006
  Q: A fire hose held near the ground shoots water at a speed of 6.5 m/s. At what angle(s) should the ...
  A: Break the velocity into components: Horizontal velocity, Vh = cos(theta)*6.5 m/s Time to go 2 meters ...
satellite orbits9/11/2006
  Q: thanx 4 ur suffecient & nice answer ..it satisfied my info lack.. but i've a unique question, if we ...
  A: OK, that's an interesting question. The result would depend on a few additional details about how ...
Physics- General Science9/11/2006
  Q: In physics the "desire of an object to keep doing what it is doing" is termed..... permanence ...
  A: The 2nd choice gave me a chuckle - thanks for that. Physics calls that characteristic inertia. ...
principles9/10/2006
  Q: what are some principles or laws in a ballon powered car?
  A: The principal principle to be used in analysis of this toy is the conservation of momentum. You ...
Newtons9/10/2006
  Q: Is a Newton a measurement of force, and if so, is 1 Newton a lot
  A: Yes, the Newton is a measurement of force, and weight. Is it a lot? The weight of 1 kilogram is ...
Energy, power9/9/2006
  Q: Find power in terms of displacement (s) if the mass of body is m and force F=Ks^(-1/3)(i.e ...
  A: Power is Work divided by time, so the result will also be in terms of time. Work is Force times the ...
Pressure9/8/2006
  Q: There is a apparatus where a test tube is covered with a nonpermeable elastic membrane and sealed in ...
  A: I will guess that the test tube contains air and the syringe contains air. So when the plunger is ...
the difference between two electromagnets9/7/2006
  Q: I have a question that I have been stuck on for ages: What is the difference between two ...
  A: I will assume your electromagnets are in solenoid shape (straight tube). As said in ...
egg drop9/7/2006
  Q: my partner and i have to build an egg dropping device. our materials are limited to wood (with a ...
  A: I have seen many questions answered on this topic. This is the first I have gotten. It seems that ...
Object sizes9/6/2006
  Q: It seems obvious that it should, but why does an object appear to get smaller when you move it ...
  A: Horizontal size is interpreted by our brain from the angle between lines from our eye to the left ...
satellite orbits9/6/2006
  Q: why satellites dont fall down over earth service ? which make it spining around earth ? ...
  A: See http://en.wikipedia.org/wiki/Orbital_velocity and ...
pk & 99channels9/5/2006
  Q: i have two questions 1.) i notice '2.5pk', a lable on our airconditioner. what does it mean? 2.)in ...
  A: 1) I find that pk is a unit used in Jakarta, Indonesia, and the Dutch language and is related to ...
Magnets and electricity9/3/2006
  Q: A lawn mower would be disqualifie because it depend on something other than the magnet itself. ...
  A: Ah, I see that you are trying to get energy out without putting energy, or work, in. Sorry, that ...
general9/1/2006
  Q: why does a small steel pin sinks and a massive ship floats
  A: Let's talk about an empty aluminum soda can first. If you seal the hole in the end so water does not ...
Magnets and electricity9/1/2006
  Q: Can electricity be created from the use of magnets? I know (and in fact have) there are magnet ...
  A: >Can electricity be created from the use of magnets? Yes, as your example shows. Also engines like ...
physics8/31/2006
  Q: a student drops a ball from a window 4.5m above the sidewalk. the ball accelerates at 9.80m/s ...
  A: Before giving you some help with your question, let me see if I can give you some general help with ...
Inducing clouds to rain8/29/2006
  Q: In thinking of ways to help minimize the potency of hurricanes...... can a cloud, say over ocean ...
  A: I believe that a cloud can be induced to rain. Whether that would help minimize the potency of ...
electricity8/27/2006
  Q: ""Suppose a point q1 is in the electric field & a unit positive charge q2 is at infinite distance ...
  A: The way you phrase your question has problems - perhaps because of some concept you need to study. ...
getting the work8/27/2006
  Q: I'm thinking how I will be able to get the work required to fill the cylindrical tank with water if ...
  A: I'm afraid there is a problem with your question. Work is defined as (F*cosTheta)*d - the product of ...
Incandescent lamp surge8/25/2006
  Q: I was once told that when you switch on an ordinary incandescent lightbulb from cold, you will get a ...
  A: In most of my calculations, assume house power of 115VAC - the US standard. Calculations show (P = ...
Projectile Motion8/24/2006
  Q: I am currently doing a major project for Year 12 Physics, investigating projectile motion - in ...
  A: This should be an interesting study for you. I refer you to the following Wikipedia pages. There are ...
train on a track8/23/2006
  Q: one more question please. A train is on a track going up a hill. It is accelerating. It has several ...
  A: Interesting question - thanks for challenging my grey matter. Let the train have 20 cars. The 20th ...
motion8/23/2006
  Q: a person in an elevator drops a coin. It takes 6 seconds to hit the floor. Will the time increase ...
  A: I'm a little puzzled that it takes 6 seconds to hit the floor. That means it fell 176.4 meters! Tall ...
Coefficiet of restitution8/22/2006
  Q: The first ball of mass m moving with a velocity u collides head on with second ball of same mass m ...
  A: The problem doesn't mention whether the balls are rolling, sliding on a frictionless surface, or ...
work8/20/2006
  Q: A man walking/carrying a briefcase is NOT doing any work, how do you explain that? I believe that it ...
  A: Work is displacement times force (or component of a force) in the direction of the displacement. If ...
physics8/18/2006
  Q: 1.which among the three methods(polygon method,1st condition of equilibrium for nonconcurrent ...
  A: 1. Maybe I don't understand the question but it seems it's asking you to compare apples and oranges. ...
newtons 3rd law8/17/2006
  Q: I am writting with regard to something a friend told me. He told me that Newtons Law could be proven ...
  A: Well, it is true that Newton's Laws are not 100% true in every condition. But discrepancies are only ...
projectile motion8/17/2006
  Q: why the result of projectile motion will be the same as long as the velocity of projectile is the ...
  A: Say that you have a small cannon which uses compressed air to fire a metal ball the size of a tennis ...
Pushy Load8/15/2006
  Q: Let's say I want to push a very heavy load. Assume the load weights 1 ton. Is there any relevance in ...
  A: Yes, there is relevance. Weight is directly related to mass (W = M*g), and mass is directly related ...
canoes8/10/2006
  Q: would a canoe sink in the ocean?
  A: I've added a followup at the bottom. Canoes are required to float in fresh water even when capsized ...
Light and more8/9/2006
  Q: I am a bioengineering major (limited calculus-based, college level physics) studying for the MCAT, ...
  A: I think I can help. 1. Remember, if you change the value of a resistor, either the voltage or the ...
ultrasonics8/9/2006
  Q: sir... can you explain the concept behind "magnetostriction oscillators using transistors"... ...
  A: I'm afraid I don't have much for you. I had not heard of magnetostriction oscillation (at least not ...
torue8/8/2006
  Q: Please explain the term torque?how torque=rFsintheta(where r is a position vector and F is the force ...
  A: When talking about linear motion, force cau