Pulling on a cylinder and energy lost to friction

[ThisIsWhyImABioMajor]

A spool of thin wire (with inner radius r = 0.50 m, outer radius R = 0.65 m, and moment of inertia Icm = 1.06 kg*m2 pivots on a shaft. The wire is pulled down by a mass M = 1.35 kg. After falling a distance D = 0.54 m, starting from rest, the mass has a speed of v = 70.200 cm/s. Calculate the energy lost to friction during that time.
Not sure where even to begin!

 

[vanesch]

Welcome to PF !

Please read our guidelines concerning homework which you agreed upon:
- post them in the appropriate homework section (in this case: intro physics; I'll move the thread after this post)

- show some work before others are even allowed to help you.

This policy is not to make life hard for you, on the contrary...

However, I'm going to give you a hint in approaching the problem:
if you know the energy at the beginning, and at the end, then the difference might have something to do with friction (because if there weren't any, both would be the same).