TPR Physics question

[DrAvery]

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This is probably a really stupid question but I just can't figure it out. In the Chapter 4 practice passage, question 4 asks "How much torque must the mechanical arm provide in order to prevent the passengers from swinging down?"

I thought it would be (600)(10)(5). but the answer key says (600)(10)(20). How is the radius 20??? I don't understand that part at all.

Thanks.

 

[milski]

I'd love to help you but cannot do much without seeing the problem.

Wild guessing: if it's an equilibrium problem, the rotation is not going to be necessary around the fulcrum, they might have picked a more convenient point.

 

[Jepstein30]

This is probably a really stupid question but I just can't figure it out. In the Chapter 4 practice passage, question 4 asks "How much torque must the mechanical arm provide in order to prevent the passengers from swinging down?"

I thought it would be (600)(10)(5). but the answer key says (600)(10)(20). How is the radius 20??? I don't understand that part at all.

Thanks.

if you give us more info, we could prob help..

not all of us have every book

 

[DrAvery]

Sorry I'll post pictures of the question so you can read it. Thanks for your help.

 

[DrAvery]

and the question:

 

[milski]

Strange, I actually agree with you that it should be 600 x 10 x 5. 20 is 4x5 but that would not be the correct answer even if there were 4 carriages, since they would balance each other out. I honestly don't know what they had in mind, is there any explanation in the answer or just a number?

Btw, that is one crazy ride! 😱