Physics B Free-Response 2012 Question Two Simulation
A small and a large sphere, of mass M and 3M respectively, are arranged as shown on the left side of the figure above. The spheres are then simultaneously dropped from rest. When the large sphere strikes the floor, the spheres have fallen a height H. Assume air resistance is negligible. Express all answers in terms of M, H, and fundamental constants, as appropriate.
(a) Derive an expression for the speed bu with which the large sphere strikes the floor
Immediately after striking the floor, the large sphere is moving upward with speed bu and collides head-on with the small sphere, which is moving downward with identical speed bu at that instant. Immediately after the collision, the small sphere moves upward with speed Su and the large sphere has speed Lu .
(b) Derive an equation that relates bu , Su , and Lu .
