a stell ball of mass m suspended by a thread of lenght l. the ball is then released when the thread is horizontal. at the bottom of this path, the ball strikes a block of mass M initially on a frictionless surface. the collision is elastic. find:
a. the speed of the ball just after colliion
b. the speed of the block just after collision
c. the fraction of the ball's kinetic energy that was converted to heat.