# Homework Help: Moment of inertia

1. Feb 17, 2008

### totalmajor

1. The problem statement, all variables and given/known data

A light, flexible rope is wrapped several times around a hollow cylinder with a weight of 55.0 N and a radius of 0.25 m, that rotates without friction about a fixed horizontal axis. The cylinder is attached to the axle by spokes of a negligible moment of inertia. The cylinder is initially at rest. The free end of the rope is pulled with a constant force P for a distance of 3.00 m, at which point the end of the rope is moving at 4.00 m/s. If the rope does not slip on the cylinder, what is the value of P?

2. Relevant equations

v=$$\omega$$r
$$\alpha$$=$$\tau$$/I
I=MR^2

3. The attempt at a solution

Alright, I honestly don't know where to start with this problem. It's review we're doing and I know the basics of inertia but nothing past that!

Can anybody help me start?

Thanks alot,
Peter

2. Feb 18, 2008

### andrevdh

work done by P on the cylinder = change in kinetic energy of the cylinder