Finding the rate of change of angular momentum

[Heat]

Homework Statement

I've uploaded a pic of the problem and my work at the link below:

http://i.imgur.com/K4ukj.jpg"

Homework Equations

I = mR^2 w



Hopefully everything thus far is correct, I'm stuck at finding the rate of change. From what I understood it's essentially the derivative of Angular Momentum with respect to time. Thank you in advance.

 

[Pi-Bond]

The rate of change of angular momentum is torque, or the moment of inertia multiplied by angular acceleration.

 

[Heat]

Thank you Pi-Bond. Does my approach for getting the angular momentum appear to be correct?

 

[Pi-Bond]

Yes, that appears to be correct.