There is a box of mass m on a wedge of mass M with angle θ (the triangle also has a angle of 90 degrees). I need to find the force applied on the little mass, this is what I got: F=-mgsinθ+Mgsinθ Where the first term refers to the force of gravity applied to the mass m and the second term refers to the normal force applied on m by M. I think my mistake is the normal force because looking at the limits when M is really big, the mass m moves in the opposite direction that gravity pushes it. Can someone help me set this force up? P.S. the surface of the wedge is frictionless and the surface in which the wedge lies on is frictionless.