Question

A man fires a bullet of mass 200 g at a speed of 5 m/s. the gun is of one kg mass. by what velocity the gun rebounds backwards?

Answer 1

We know that

momentum before collision = momentum after collision

And momentum = mass × velocity

=> Momentum before collision

= (1 + 0.2 kg) × 0

(since the body is at rest before firing)

=> momentum before collision = 0 kg m/s

Now let the rebound velocity of gun be v

So momentum after collision

= 1 × v + 0.2 × 5

=> v + 1

But momentum before collision = momentum after collision

=> 0 = v + 1

=> v = - 1 m/s

Hope it helps dear friend ☺️