Chapter 9, Problem 93P

A block of mass M is moving at speed r’₀ on a frictionless surface that ends in a rigid wall, heading toward a stationary block of mass nM, where n ≥ 1 (Fig. 9.30). Collisions between the two blocks or the left-hand block and the wall are elastic and one-dimensional. (a) Show that the blocks will undergo only one collision with each other if n ≤ 3. (b) Show that the blocks will undergo two collisions with each other if n = 4. (c) How many collisions will the blocks undergo if n = 10, and what will be their final speeds?

FIGURE 9.30 Problem 93