From a gun weighing 4 kg, when fired, a bullet takes off at a speed of 600 m / s. In this case

From a gun weighing 4 kg, when fired, a bullet takes off at a speed of 600 m / s. In this case, the gun experiences recoil, that is, it moves in the opposite direction at a speed of 0.3 m / s. Determine the mass of the bullet.

Initial data: m1 (gun weight) = 4 kg; V2 (bullet velocity after firing a gun) = 600 m / s; V1 (the speed that the gun will acquire after firing) = 0.3 m / s.

Since before the shot the speed of the gun and the bullet were equal to zero, the mass of the bullet can be calculated from the equality (the law of conservation of momentum): | m1 * V1 | = | m2 * V2 |, whence m2 = m1 * V1 / V2.

Let’s calculate: m2 = 4 * 0.3 / 600 = 0.002 kg or 2 g.

Answer: The mass of a rifle bullet is 2 grams.