1. The problem statement, all variables and given/known data A small sphere is dropped from rest at a height 'h' above a plane inclined at an angle θ to the horizontal ( < 90degrees ). Given that the sphere loses no energy on impact, show that the distance down the plane between this impact and the next is 8hSinθ. 2. Relevant equations 3. The attempt at a solution Presumably, we need to consider a rotated reference frame oriented to apply to the given inclined plane. The component along the plane will have a Sinθ component, but I can't really put my finger on how to solve this.