1. The problem statement, all variables and given/known data I have a problem when doing math for pulley problems - if not at least one of the rope segments in independent, I do not seem to be able to compute the speed of given objects. For instance: This is a very easy problem. Sa+3Sb=l and derive for speed; you don't really have to even go that far because you can see 3 lengths of rope are moved for motion in A, so the motion of d is 1/3 the speed of the motion of A. This problem, however, confuses me: Because none of the ropes are independent, as A was in the beginning, I can't set up enough equations to solve this formally! 2. Relevant equations Position derives to speed. No real governing equations. 3. The attempt at a solution I see that 4 lengths of rope move and area all directly connected to the cart, so it makes sense that the motion of A is 1/4 the motion of P. However, I can't show this formally.