. 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.

 

Best Answer

Sol. Firstly, we will calculate the momentum of both rifle and bullet separately.

Momentum of bullet = Mass of bullet × Velocity of bullet

 =  50/1000 × 35

 = 0.05 × 35

 = 1.75 kg m/s (i)

And,

Momentum of rifle = Mass of rifle × Velocity

 = 4v kg m/s (ii)

We know that,

According to the law of conservation of momentum:

Momentum of bullet = Momentum of rifle

1.75 = 4v [From (i) and (ii)]

v = 1.75/4

v = 0.4375 m/s

Therefore, the recoil velocity of the rifle is 0.4375 m/s

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