1. The problem statement, all variables and given/known data Block A slides on a frictionless ramp, as shown (in the attachment). At the instant, the block is moving up the ramp with speed V. Block B rests on top of A, and does not slip, due to friction between A and B. What is the direction of the friction force acting on B? 2. Relevant equations F=ma 3. The attempt at a solution In order for the block B to move it has to have a net force on it, so I assume that the only way for this to happen is if the frictional force is directed up the ramp?