A 23 g bullet traveling 220 m/s penetrates a 4.2 kg block of wood and emerges cleanly at 140 m/s.

Question

If the block is stationary on a frictionless surface when hit, how fast does it move after the bullet emerges?

Answer 1

conservation of momentum:

M*0+23*220=M*Vf+23*140
M = 4200 grams solve for Vf

Answer 2

230

Answer 3

140 m/s