Question

A bullet of mass 10g is fired from a gun of mass 6kg with a velocity of 300m/s. Calculate the recoil velocity of the gun?​

Answer 1

Answer: The velocity of the gun = -0.5m/s

Explanation: Mass of bullet=10 g

=10100 kg

=0.01 kg

Velocity of bullet=300 m/s

Mass of gun=6kg

And, Recoil velocity of gun=? (To be calculated)

Now, putting these values in relation :

Mass of bullet ×Velocity of bullet×=mass of gun ×Recoil velocity of gun

We get : 0.01×300=6× Recoil velocity of the gun ,

So, Recoil velocity of gun=0.01×3006

=0.5 m/s

Note. The above problem can also be solved by calculating the momentum of bullet and the gun separately as follows :

Momentum of bullet=Mass of bullet×Velocity of bullet

=0.01×300

= 3 kg. m/s

Now, suppose the recoil velocity of the gun is v m/s.

So, the Momentum of gun=Mass×Recoil velocity of the gun

=6×v kg m/s

According to the law of conservation of momentum :

So, 3=6×v

And, v=36m/s

Recoil velocity of gun,v=0.5 m/s