A 13 g bullet traveling 215 m/s penetrates a 2.0 kg block of wood and emerges cleanly at 157 m/s.

A 13 g bullet traveling 215 m/s penetrates a 2.0 kg block of wood and emerges cleanly at 157 m/s. If the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?