In Figure a, a 3.50 g bullet is fired horizontally at two blocks at rest on a

Question:

In Figure a, 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 v1 = 0.630 m/s and v1 = 1.40 m/s (Figure b). Neglecting the material removed from block I by the bullet, find the speed of the bullet as it(a) Leaves and(b) Enters block1.