A bullet of mass 20g leaves the gun with a velocity of 200 m/s. If the mass of gun is 2kg then the speed of recoil of the gun is:

Explanation

The principle of conservation of momentum states that the total momentum of an isolated system remains constant. Here, the gun and the bullet together form a system. So, the momentum of the gun and the bullet before firing will be equal to the momentum of the gun and the bullet after firing.Initial momentum = Final momentum(mass of gun) x (velocity of gun) = (mass of bullet) x (velocity of bullet) + (mass of gun) x (velocity of recoil)Substituting the values, we get:(2 kg) x 0 m/s = (0.02 kg) x (200 m/s) + (2 kg) x (velocity of recoil)Solving for the velocity of recoil, we get:velocity of recoil = - (0.02 kg) x (200 m/s) / (2 kg) = -2 m/sThe negative sign indicates that the recoil is in the opposite direction to the direction of the bullet. So, the magnitude of the speed of the recoil of the gun is 2 m/s.