1. The problem statement, all variables and given/known data All of this is in the attachment, but here is the question anyways. "Two blocks of masses A, 50 kg and B, 30 kg are connected to a mass*less pulley which is connected to a wall. Determine the velocity of block B after it moves 0.5 m from its original position. Assume no friction and that the blocks start from rest" 2. Relevant equations 3. The attempt at a solution Obviously, I don't need help finding a solution but I can not wrap my head around how my professor got the relationship that [itex] v_A = v_B [/itex]. I see that the length of the movement of one block is equal to the other, but why do they have the same sign? If we define the positive x-axis to be in the direction that block A moves "down" (towards the right) then block B would move "up" so their position and their velocities would have to be opposite of each other? Can anyone explain to help me see what is going on?