# Homework Help: Two blocks of mass connect to a pulley

1. Aug 7, 2012

### kitsunebell74

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

Blocks of mass and are connected by a massless string that passes over the pulley in the figure . The pulley turns on frictionless bearings, and mass slides on a horizontal, frictionless surface. Mass is released while the blocks are at rest.

2. Relevant equations

I found a1 for the mass of block one (m1).
a1 = m2g/(m1+m2)
T = (m1*m2*g) / (m1 + m2)
and tension in the string (which is the same everywhere)

3. The attempt at a solution

Now I must find a1 with a mass of the pulley (mp) and radius R.

So far I have drawn my free body diagrams for block 1, block 2, and the pulley. I was able to sum up my forces but I am having trouble summing up the net torque. Will the tensions from the two block be separated? Like this Tnet = r*T1 + r*T2

Last edited: Aug 7, 2012
2. Aug 7, 2012

### tiny-tim

welcome to pf!

hi kitsunebell74! welcome to pf!
yes, the tensions will be different, and τnet = r*T1 - r*T2

now apply the rolling constraint a = rα

3. Aug 8, 2012

### kitsunebell74

Thanks for the greeting. I figured it out. :)