Question

A gun of mass 1.5 kg fires a bullet of mass 20 g with a speed of 50 m/s calculate -(a) Initial momentum of gun and (b) moemtum gained gained by bullet after firing (c) Recoil velocity of the gun.​

Answer 1

Mass of Gun, Mg= 1.5 kg

Mass of Bullet, Mb= 20 g

Velocity of Bullet, Vb= 50m/s

Recoil Velocity of Gun, Vg= ?

Linera Momentum

Mg. Vg+Mb.Vg=0

$1.5×Vg + \frac{20}{1000} \times 50 = 0$

$1.5 \times Vg + 1 = 0$

$1.5 \: Vg = - 1$

$Vg = \frac{1}{1.5}$

$Vg = 0.67 \: ms {}^{ - 1}$

$\huge\red{a)}$

Initial momentum of gun

p=mv

p=1.5 × 0

p=0

$\huge\red{b)}$

Momentum gained gained by bullet after firing

p=mv

p=1.5×0.67

p=1.005m/s

$\huge\red{c)}$

Recoil velocity of the gun

Recoil velocity of the gun=Vg

Vg=0.67 m/s