Question

A shell of mass $0.020kg$ is fired by a gun of mass $100kg$. If the muzzle speed of the shell is $80m{s}^{-1}$. what is the recoil speed of the gun?

Answer 1

Mass of gun M = 100kg

mass of shell m = 0.020kg

Velocity of shell v = 80m/s

Recoil velocity of Gun V=?

initial velocities of both gun and shell will be zero

so, the initial momentum of the system will be zero.

According to the law of conservation of momentum,

Initial momentum = Final momentum

so,

0=mv-MV

∴v=mv/M

= $\frac{0.020\times 80}{100}$

=0.016 m/s

∴recoil velocity of Gun=0.016m/s