Torque with pulleys and bucket of water

[mikefitz]

Imagine a frictionless pulley (a solid cylinder) of unknown mass M and radius r = 0.41 m is used to draw water from a well. A bucket of mass m = 1.53 kg is attached to a cord wrapped around the cylinder. A bucket starts from rest at the top of the well and falls for t = 2.04 s before hitting the water h = 2.87 m below the top of the well. Neglect the mass of the cord.

t = F*R
t=(1.53*9.81) * .41

t = 6.15 Nm??

 

[Doc Al]

What's the question? (Find the unknown mass of the pulley?)

Hint: What directly exerts the torque on the cylinder is the tension in the rope, not the weight of the bucket.

 

[mikefitz]

sorry, the question is asking what the torque is; i can't seem to figure it out for some reason?

 

[Doc Al]

Find the tension in the rope.

Hints: Analyze the forces acting on the bucket. Apply Newton's 2nd law. (What's the acceleration of the bucket?)