1. The problem statement, all variables and given/known data Find out the acceleration of the rod A and the wedge B in the arrangement if the ratio of mass of the wedge to that of the rod equals [tex]\eta[/tex], and the friction between all contact surfaces is negligible 2. Relevant equations Mass of rod = m, Mass of wedge = M mg - [tex]N cos \alpha[/tex] = ma, downwards 3. The attempt at a solution Normal reaction is perpendicular the wedge surface and I don't know if it has a component that can accelerate the wedge to the right. If the force is moving to the left, surely the wedge can't be accelerated to the left. I need to know which force accelerates the wedge to the right. I'm thinking that the normal reaction has the component [tex]N sin \alpha[/tex] directed to the left. If I knew which component of force was directed to the right, I could solve the remaining part of it.