Question

A gun moves backward when a shot is fired from it
(a) Choose the correct statement
(1) The Momentum of the gun is greater than that of the shot
(ii) The momentum acquired by the gun and shot have the same magnitude
(iii) Gun and shot acquire the same amount of kinetic energy
(b) A shell of mass 0.020kg 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?​

Answer 1

Answer:

a⟩ The Momentum of the gun is greater than that of the shot.

b⟩ 40m/s

Answer 2

Answer:

Option (ii) is correct  "The momentum acquired by the gun and shot have the same magnitude"

Recoil velocity of the gun = 0.016 m/s

Explanation:

(a) We know the relation of conservation of momentum:

"The momentum of a system is constant, provided no external forces are applied in the system."

mv = constant --------------------------(1)

m₁ v₁ = m₂ v₂ -----------------------------(2)

So, the more the mass, the less is the momentum.

Therefore, option (ii) is correct  "The momentum acquired by the gun and shot have the same magnitude"

(b) mass of the shell = 0.02kg

    mass of the gun = 100kg

    muzzle speed = 80m/s

Now, using eq(2) we get

     m₁ v₁ = m₂ v₂

=> 0.02 x 80 = 100 x v₂

=> v₂ = 0.016 m/s

[where v₂ = recoil velocity of the gun]