Question

When a stationary rifle fires a bullet, the KE of the rifle + billet system increases to conserve the momentum. From where this energy is coming from? Or in this situation does the energy conservation law don’t hold good.

Answer 1

1. Given data:
   When a stationary rifle fires a bullet, the K.E of the rifle + bullet system increases to conserve the momentum.
2. This energy comes from elastic potential energy stored in the spring and the chemical energy of gun powder.
3. Because of this elastic potential energy and chemical energy of gun powder converts to the kinetic energy of the bullet and recoil energy of the rifle. so. In this situation, the energy conservation law does hold good.