Question

4.5 kg rifle fires a 0.05 kg bullet. If the bullet leaves thebarrel of the rifle with a speed of 670 m/s, calculate the recoilvelocity of the rifle.

Answer 1

Answer: - 7.44 m/s

Explanation:

When the bullet is shot, it moves forward with a large momentum and the riflr moves backward with an equal momentum

Let m represent the mass of the bullet and v represent the velocity of the bullet

Let M represent the mass of the rifle and V represent the velocity of the rifle

Recall, momentum = mass x velocity. Thus,

mv + MV = 0

MV = - mv

V = - mv/M

From the information given,

M = 4.5

m = 0.05

v = 670

By substituting these values into the formula,

V = - (0.05 x 670)/4.5

V = - 7.44 m/s

The recoil velocity of the rifle is - 7.44 m/s