A 20-g bullet moving at 1000 m/s is fired through a one-kg block of wood emerging at a speed of 200 m/s.If the block had been originally at rest and is free to move,what is its resulting speed?
A) 800 m/s
B) 80 m/s
C) 16 m/s
D) 8 m/s

Question

Quizplus · Accepted Answer

By conservation of momentum:
Initial momentum = final momentum 
(20 g) (1000 m/s) = (1 kg + 20 g) (v)
v = (20 g) (1000m/s) / (1 kg + 20 g) = 16.13 m/s
Therefore, the resulting speed of the block is approximately 16 m/s.

A 20-G Bullet Moving at 1000 M/s Is Fired Through