Question

A 10kg stationary gun is loaded with a 10g bullet. It is fired, with the bullet travelling at 100m/s. What is the recoil speed of the gun?

Answer 1

Explanation:

Let initial velocity of recoil of gun be v

Given:

Mass of gun, m1 = 10 kg

Mass of bullet, m2 = 10 g = 0.010 kg

Now, initial velocity of gun = v

initial velocity of bullet = 100 m/ s

So, initial momentum of gun = 10 × v

initial momentum of bullet = 0.010 × 100

= 1 kg m/ s

Using law of conservation of momentum;

Momentum of gun = Momentum of bullet

10 × v = 1

v = 1/ 10

v = 0.1 m/ s

Therefore, recoil speed of the gun is 0.1 m/ s.