From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m s-1. Calculate the initial recoil velocity of the rifle.

Explanation

initial mass of rifle, m1 = 4 kg Let initial velocity of recoil pf rifle = u1
∴ Initial momentum of the rifle = 4 kg × i’. Initial mass of bullet, m2= 50 g \frac { 50 }{ 1000 } = 0.05 kg Initial velocity of bullet v2 = 35 m s-1
∴ Initial momentum of bullet = 0.05 kg × 35 m s-1 By the law of conservation of momentum, Momentum of the rifle = Momentum of bullet