1. The problem statement, all variables and given/known data In the graph shown in the picture, an expression for the acceleration of the pulleys is obtained. 2. Relevant equations 3. The attempt at a solution The thing i don't understand is, how do we find the angular momentum for the system? In class, I was told that the angular momentum for the system was: Ltot = MvR + m1vR + m2vR However, why do we pick the same velocities for the objects? (aren't they accelerating, and thus having different velocities?). As well, why do we choose the radius of the pulley for mass 1 and mass 2 to be that way? (isn't angular momentum calculated for objects in linear motion as the distance from the origin, which in this case is the axle of the pulley?). Thank you very much.