I'm not sure how to do the last problem in this pdf:

Question

h t t p : / / t i n y u r l . c o m / y 9 q f 4 7 4

Any help would be appreciated. Thank you!

Answer 1

http://tinyurl.com/y9qf474
well, you know that I=sum mr^2= you can do that for the masses.

Then, pulling force is 4mg, and torque= I alpha
4m*g*r=I above*angular acceleartion
but angular acceleration= a/r

so you can solve for a.

c) energy work in block going down= energy in rotation+ energy in downward block