# What is the recoil velocity of a rifle, stationary when fired, if the mass of the rifle is 4 kg

What is the recoil velocity of a rifle, stationary when fired, if the mass of the rifle is 4 kg, the mass of the bullet is 8 g, and the velocity of the bullet is 600 m / s?

m1 = 4 kilograms is the mass of the rifle;

m2 = 8 grams = 0.008 kilograms – bullet weight;

v2 = 600 meters per second – bullet speed.

It is required to determine the speed of the rifle at recoil v1 (meter per second).

Since, according to the condition of the problem, the rifle is stationary when fired, which, according to the law of conservation of momentum (momentum):

m1 * v1 = m2 * v2, hence:

v1 = m2 * v2 / m1 = 0.008 * 600/4 = 4.8 / 4 = 1.2 meters per second.

Answer: The recoil speed of the rifle is 1.2 meters per second.

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.