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on a wrench with 100 N of force 20 cm from the rotation point. 4. John pulls a)

ID: 1775032 • Letter: O

Question

on a wrench with 100 N of force 20 cm from the rotation point. 4. John pulls a) How much torque does he apply if he is pulling at a right angle to the wrench? b) How much torque does he apply if he is pulling at a 30 degree angle to the wrench? c) How much torque does he apply if he is pulling parallel to the wrench? A hollow cylinder with radius 30 cm and mass 4 kg is rotating about its central axis at 20 r 10 N frictional force is applied to the outer rim of the cylinder. How much torque is applied to the cylinder? 5. a) b) What is the angular acceleration of the cylinder? c) How long will it take the cylinder to come to rest?

Explanation / Answer

4)

Given:

Force F = 100N

Distance r = 20cm = 0.20m

Torque is given by the cross product of r and F:

T = r x F = rFsin(th)

where th is the angle.

So, for th = 90 degrees

T = (0.20)(100)sin(90) = 20 N-m

for th = 30 degrees

T = (0.20)(100)sin(30) = 10 N-m

for th = 0 degrees

T = (0.20)(100)sin(0) = 0 N-m