From a rifle of mass 4kg, a bullet of mass 50g is fired with an initial velocity of 35 ms-1 - Science - Force and Laws of Motion

Question

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

Kranav Sharma · Accepted Answer

Given:
Mass of rifle = 4 kg

Mass of
bullet = 50 g = 0 05 kg

Initial
velocity of the bullet = 35 m/s

Let the
recoil velocity of the rifle be = v
m/s

Since
in the beginning both the rifle and bullet are at the rest (when
bullet is not fired)

Therefore,
initial momentum = 0

When
the bullet is fired both bullet and rifle moves

Therefore,
final momentum = momentum of bullet + momentum of rifle

so,

Final
momentum = (0 05 Ã— 35) + (4 x v)

= 1 75
+ 4v

by
applying law of conservation of momentum we get

1 75 +
4v = 0

or

4v = -1
75

thus,
recoil velocity of the rifle will be

v = -0
4375 m/s

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