Question

A bullet of mass 50 gram is fired from a gun of mass 5 kg with an initial velocity of 40 metres per second what is the recoil velocity of the gun

Answer 1

Given the mass of the gun, M = 10 kg,  mass of the bullet, m = 0.05 kg  Speed of the bullet, v = 500 m/s.  Let the velocity of recoil of the gun = V  Using conservation of momentum, we get  Momentum after = momentum before  MV – mv = 0 (as initial momentum was zero)  or, MV = mv  or, 10*V = 500*0.05  or, V = 25/10 = 2.5 m/s