Pulley question

asi123

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

Hey guys.
Look at this pulley system, I wrote down all the equations.
The pulley on the left is massless, the one on the right has the mass of m3 and radius R.
I also wrote the the torque equation of the pulley and the thing I don't understand is the what is the acceleration of the pulley (a3), is it equal to a2 or to a1?
Thanks a lot.

2. Relevant equations



3. The attempt at a solution

Attached Thumbnails

 

Doc Al

Aren't m2 and m3 (the pulley) attached?

asi123

Oh, you right...
Thanks.