Halliday, Resnick & Walker — Center of Mass and Linear Momentum: Problem 51

51 In Fig. 9-50a, a 3.50 g bullet is fired horizontally at two blocks at rest on a frictionless table. The bullet passes through block 1 (mass 1.20 kg) and embeds itself in block 2 (mass 1.80 kg). The blocks end up with speeds \(v_1 = 0.630 \text{ m/s}\) and \(v_2 = 1.40 \text{ m/s}\) (Fig. 9-50b). Neglecting the material removed from block 1 by the bullet, find the speed of the bullet as it (a) leaves and (b) enters block 1.