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tucky

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Here is two questions about torque that I am having problem figuring out:

Q: The USS Constitution’s largest anchor weighed 5443 lbs. The capstan was a drum that measured roughly 4 ft in diameter. Twelve poles, each about 12 feet long, could be stuck into the capstan. Sailors pushed on the poles, winding the anchor rope around the capstan and raising the anchor. Assume half the torque generated is lost to friction and slippage. How much force must be applied to each pole to raise the anchor? How many sailors do you think would have to man each pole?

A: Torque = r * F

Torque= 14ft *5443lb = 76202ft-lb multiply it by two because half of the torque is lost = 152404ft-lb /12 poles =12300.3ft-lb. –that just seems to high

Q: A kid turns his bike upside down and spins the tire. The spoked wheel measures 26 inches in diameter and weighs 5 lbs. The kid presses a piece of metal against the rubber tire to bring it to a halt. About how long will it take to bring the wheel to a halt if the kid presses with a force of 10 lb?

A: I am not really sure how to work this problem. I think this is a Newton 2 law problem: Sum of forces = ma

10lb = 4.54 kg * 9.8N =44.49N

I = ½ 2.27(.3302m)^2 = .1237kgm^2

44.49N=.1237kgm^2 * a/.3202m if I solve it this way I get a –115.161/s^2 acceleration which is wrong. I really do not know what to do?

Q: The USS Constitution’s largest anchor weighed 5443 lbs. The capstan was a drum that measured roughly 4 ft in diameter. Twelve poles, each about 12 feet long, could be stuck into the capstan. Sailors pushed on the poles, winding the anchor rope around the capstan and raising the anchor. Assume half the torque generated is lost to friction and slippage. How much force must be applied to each pole to raise the anchor? How many sailors do you think would have to man each pole?

A: Torque = r * F

Torque= 14ft *5443lb = 76202ft-lb multiply it by two because half of the torque is lost = 152404ft-lb /12 poles =12300.3ft-lb. –that just seems to high

Q: A kid turns his bike upside down and spins the tire. The spoked wheel measures 26 inches in diameter and weighs 5 lbs. The kid presses a piece of metal against the rubber tire to bring it to a halt. About how long will it take to bring the wheel to a halt if the kid presses with a force of 10 lb?

A: I am not really sure how to work this problem. I think this is a Newton 2 law problem: Sum of forces = ma

10lb = 4.54 kg * 9.8N =44.49N

I = ½ 2.27(.3302m)^2 = .1237kgm^2

44.49N=.1237kgm^2 * a/.3202m if I solve it this way I get a –115.161/s^2 acceleration which is wrong. I really do not know what to do?

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