In this problem, "m" slides down "M" (that is inclined at angle alpha) to the point "P" at the bottom-right of the triangle. "m" starts with zero velocity and "M" starts with zero velocity. There is zero friction between "m" and "M". There is also zero friction between "M" and the surface that it rests on (not shown in picture). So the questio is what is the velocity of "m" when it reaches the "P"? I don't even know how to approach this problem, so I dont have any work done, but my teacher told me that I would have to use the conservation of linear momentum and mechanical energy. Thanks for all the help.