1. The problem statement, all variables and given/known data Two objects of equal masses A and B are connected to a system of pulleys as shown in the figure uploaded. The pulleys are assumed to be smooth. Calculate the acceleration of A. 2. Relevant equations F=ma 3. The attempt at a solution Mg-T=ma I can't figure out the second equation for b becaus I think it is attached to the pulley and will remain stationary. However, in the proposed solution, there's an equation for the movement of b too. How is that possible?