Question

A bullet of mass 50 gram is fired from a gun of mass 6 kg with a velocity of 400 m per second calculate the recoil velocity of the gun

Answer 1

Mass of the bullet = 50 grams = 0.05 kg

Mass of the gun = 6 kg

Velocity of the bullet (v) = 400 m/s

Let the recoil velocity of the gun be v.

Since, before firing the gun and the bullet are at rest. Hence, the initial momentum is zero.

Now, the final momentum should also be zero because the forces between the gun and the bullet are internal.

Final momentum = 0.05 × 400 + 6 × v = 0

6v = - 20

v = $\frac{-20}{6}$

v = - 3.33 m/s

Hence, the recoil velocity is -3.33 m/s. The negative sign shows that it will be in the backward direction.

Answer 2

first convert m1 , bullet mass into kg

50/1000 = 0.05kg

v1, velocity of bullet = 400m

m2, mass of gun= 6kg

we know that

m1.v1 = m2v2

0.05 × 400 = 6 × v2

v2, recoil velocity = -10/3

because the velocity is in opposite direction