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# Physics/A few questions on Physics

Question
I am a Physics 1 student and I have a few questions that I don't understand.
1. When an object is spun in a circle horizontally, what keeps it from falling down? Doesn't it have the Force of gravity acting on it, but how does it remain up?
2. When I hold  a string with something attached to it and then yank it very hard, how does the force get converted upwards and pull that object up?
3. Acceleration is m/s^2 right? Then why is it when you use d=1/2(a)t^2 the acceleration becomes 2m/s^2????

Hello Philip,

1.  Yes it does have gravity acting on it. Take a look at this wikipedia page.
http://en.m.wikipedia.org/wiki/Gyroscope
Go to the Properties section. That will explain how a gyroscope stays upright. It also explains how a toy spinning top stays upright.
http://en.m.wikipedia.org/wiki/Top

2. What direction are you jerking it? If you jerk upwards, that might explain why the "something" is pulled up.

3. Acceleration is in units of m/s^2, yes. The magnitude of a depends on what values you plug in for d and t. If d = 1 m and t = 1 s, when you solve for a, it will be 2 m/s^2.

I hope this helps,
Steve

Physics

Volunteer

#### Steve Johnson

##### Expertise

I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

##### Experience

I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University