A bullet takes off from the rifle at a speed of 700 m / s. The rifle, upon recoil, acquires a speed of 1.6 m / s

| June 17, 2021 | education

A bullet takes off from the rifle at a speed of 700 m / s. The rifle, upon recoil, acquires a speed of 1.6 m / s. Determine the mass of the rifle if the mass of the bullet is 10 grams.

Vp “= 700 m / s.

Vw “= 1.6 m / s.

mp = 10 g = 0.01 kg.

mv -?

According to the law of conservation of momentum for a closed system, a rifle-bullet: mw * Vw + mp * Vp = mw * Vw “+ mp * Vp”, where mw are the mass of the rifle, mp is the mass of the bullet, Vp, Vw2 is the speed of the bullet and rifle before the shot , Vп “, Vв” – the speed of the bullet and rifle after the shot.

The velocity of the rifle and the bullet before the shot was Vp = Vw = 0 m / s, they were at rest.

The impulse conservation law will take the form: 0 = mw * Vw “+ mp * Vp”.

mw * Vw “= – mp * Vp”.

The “-” sign means that the direction of movement of the bullet and the rifle after the shot has the opposite direction.

mv = mp * Vp “/ Vv”.

mw = 0.01 kg * 700 m / s / 1.6 m / s = 4.4 kg.

Answer: the rifle has a mass of mw = 4.4 kg.



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