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Question
7. The acceleration of an object varies directly as the force acting on it. If a force of 240 newtons causes an acceleration of 150 m/sē, what force will cause an acceleration of 100 m/sē?
9. A public opinion poll found that out of a sample of 450 voters, 252 favored a school bond issue. If 20,000 people voted, how many are likely to vote for the bond measure?
10. The speed of an object falling from rest in a vacuum is directly proportional to the time it has fallen. After an object has fallen for 1.5 seconds, its speed is 14.7 m/s. What is the speed after it has fallen 5 seconds?
11. Newton's law of cooling states that the rate at which an object cools varies directly as the difference between its temperature and the temperature of the surrounding air. At the moment a steel plate at 270 degrees Celsius is placed in air that is at 20 degrees Celsius, its rate of cooling is 50 degrees Celsius per minute. How fast is it cooling when the plate temperature is 100 degrees Celsius?
12. The centrifugal force acting on an object moving in a circle is directly proportional to the square of the speed of the object. If the force is 2240 newtons when the object is moving 8 m/s, what is the force when the object is moving at 12 m/s?
13. The speed of an object falling from rest is directly proportional to the square root of the distance the object has fallen. When an object has fallen 36 ft., its speed is 48 ft/s. How much farther must it fall before its speed is 80 ft/s?
7 Q: 240 => 150 m/sē; 100?
The answer would be to divie by 240 and multiply by 100.
In other words, it would be (100/240)150
9. If sample showed 252 out of 450, that's 126/225.
Multiply 20,000 by 126/225 go get the answer.
10. After 1.5, speed = 14.7; speed after 5?
To get the answer, take the speed of 14.7 and adjust by time.
Note that you need to multiply by 5 and divide by 1.5.
11. Cooling proportional to difference in temperature.
If steel is 270° celsius, air is 20° celsius, cooling rate = 50°/m.
Cooling rate at 100° celsius?
The starting difference is 270-20 = 250.
The current difference is 100-20 = 80.
Multiply the cooling rate by 80/250 = 8/25
to get the new cooling rate.
12. Centrifugal force is 2240 at 8 m/s;
centrifugal force is proportional to speed;
centifigul force at 12 m/s?
The difference is speed is 12/8, which is 1.5
The amount the centrifugal force is affected is by the square of 1.5.
The square of 1.5 is 2.25. Multiply the centrifgual force by 2.25.
13. Speed of fall proportional to √(distance fallen).
At 36 feet, speed if 48ft/s. How much farther until speed is 80ft/s?
Take 80/48, which is 5/3, square it, and and multiply by 36 feet.
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Scott A Wilson
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I can answer any question in general math, arithetic, discret math, algebra, box problems, geometry, filling a tank with water, trigonometry, pre-calculus, linear algebra, complex mathematics, probability, statistics, and most of anything else that relates to math. I can even tell you it takes me over 2,000 steps to go a mile, but is that relevant?
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Experience in the area; I have tutored people in the above areas of mathematics for almost two years in AllExperts.com. I have tutored people here and there in mathematics since before I received a BS degree almost 25 years ago. In just two more years, I received an MS degree as well, but more on that later.
I tutored at OSU in the math center for all six years I was there. Most students offering assistance were juniors, seniors, or graduate students. I was allowed to tutor as a freshman.
I tutored at Mathnasium for well over a year.
I worked at The Boeing Company for over 5 years.
I received an MS degreee in Mathematics from Oregon State Univeristy.
The classes I took were over 100 hours of upper division credits in mathematical courses such as
calculus, statistics, probabilty, linear algrebra, powers, linear regression, matrices, and more.
I graduated with honors in both my BS and MS degrees.
Past/Present Clients: College Students at Oregon State University, various math people since college,
over 7,500 people on the PC from the US and rest the world.
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My master's paper was published in the OSU journal.
The subject of it was Numerical Analysis used in shock waves and rarefaction fans.
It dealt with discontinuities that arose over time.
They were solved using the Leap Frog method.
That method was used and improvements of it were shown.
The improvements were by Enquist-Osher, Godunov, and Lax-Wendroff.
Education/Credentials
Master of Science at OSU with high honors in mathematics.
Bachelor of Science at OSU with high honors in mathematical sciences.
This degree involved mathematics, statistics, and computer science.
I also took sophmore level physics and chemistry while I was attending college.
On the side I took raquetball, but that's still not relevant.
Awards and Honors
I earned high honors in both my BS degree and MS degree from Oregon State.
I was in near the top in most of my classes. In several classes in mathematics, I was first.
In a class of over 100 students, I was always one of the first ones to complete the test.
I graduated with well over 50 credits in upper division mathematics.
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