Thread: Physics Quiz 12
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Unread 04-03-2016, 14:19
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Re: Physics Quiz 12

Quote:
Originally Posted by Ether View Post
Do you want to continue working on it by yourself? Or shall I invite high-school teachers to chime in?


Sorry, I had homework...what I have is below, but I welcome all other input.

I think I fixed the ramp / rail / cart thing in my previous post (I should really proofread more carefully).


Part 2:
I calculated the torque produced by gravity around point G, and the torque from tension around point E. I then subtracted the two values to find the overall torque. For example, for point A:

torque_gravity = (m*g)(distance_AG)(angle_AG to vertical)
= 15582*1.2*sin(20deg)
= 6395
torque_tension = (T)(distance_AE)(angle AE to ET)
= 5448*1.7*sin(140deg)
= 5953
So the overall torque around point A is 442 N*m in the counterclockwise direction.

With this method, I got that all four rollers have torque in the counterclockwise direction, of magnitudes 442, 402, 24082, and 24092 Nm (A, B, C, D).

This is where I get stuck again, because I don't know how this correlates to figuring out which rollers make contact--is it the magnitude of the torque? The difference in the respective pairs?
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