Cylinder+String Rolling w/o slipping

[Imuell1]

Homework Statement

A uniform cylinder of mass M and radius R has a string wrapped around it. The string is held fixed, and the cylinder falls vertically. (a) Show that the acceleration of the cylinder is downward with a magnitude a=2g/3. (b) Find the tension in the string.

Homework Equations

I=1/2MR²

The Attempt at a Solution

Not sure how to start, does it involve the conservation of mechanical energy?

 

[CaptainEvil]

Try Newton's methods.

Draw a freebody diagram for the cylinder, include all the forces acting on it and use Newton's second law, along with torque = Ialpha, to solve for your unknowns