A bullet of mass 10 g is horizontally fired with velocity 300 m s-1 from a pistol of mass 1 kg. What is the recoil velocity of the pistol?

The recoil velocity of the pistol is determined using the law of conservation of linear momentum. Initially, both the pistol and the bullet are at rest, so the total initial momentum is zero. According to the law, the total momentum after firing must also be zero. The mass of the bullet is 10 g, which is 0.01 kg. Let the velocity of the bullet be v = 300 m/s and the mass of the pistol be M = 1 kg. The momentum of the bullet is (0.01 kg * 300 m/s) = 3 kg m/s. To conserve momentum, the pistol's momentum (M * V) must be -3 kg m/s. Solving for the recoil velocity (V), we get 1 kg * V = -3 kg m/s, resulting in V = -3 m/s. The negative sign indicates that the pistol moves in the opposite direction to the bullet.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 9: The Amazing World of Solutes, Solvents, and Solutions > Conversion factor for density > p. 141