A shell of mass 0.020 kg is fired by a gun of mass 100kg. if the muzzle speed of the shell is 80m/s what is the recoil speed of the gun?
Mass of the gun, M= 100 kg
Mass of the shell, m= 0.020 kg
Muzzle speed of the shell, v = 80 m/s
Recoil speed of the gun = V
Both the gun and the shell are at rest initially.
Initial momentum of the system = 0
Final momentum of the system = mv - MV
Here, the negative sign appears because the directions of the shell and the gun are opposite to each other.
According to the law of conservation of momentum:
Final momentum = Initial momentum
mv - MV= 0
∴ V = mv / M
= 0.020 x 80 / 100 x 1000
= 0.016 m/s
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