일반물리학 1 — Center of Mass and Linear Momentum: Problem 64

64 A steel ball of mass 0.600 kg is fastened to a cord that is 70.0 cm long and fixed at the far end. The ball is then released when the cord is horizontal (Fig. 9-57). At the bottom of its path, the ball strikes a 2.80 kg steel block initially at rest on a frictionless surface. The collision is elastic. Find (a) the speed of the ball and (b) the speed of the block, both just after the collision.