Question

A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant the gun fires bullets of mass 10 gm with a velocity of 500 m/sec with respect to the car. The number of bullets fired per second is ten. The average thrust on the system is

Answer 1

Question:

• A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant the gun fires bullets of mass 10 gm with a velocity of 500 m/sec with respect to the car. The number of bullets fired per second is ten. The average thrust on the system is??

Solution :

mass of the bullet = 10 gm = 0.01 kg

velocity of the bullet = 500 m/s

First we need to find the momentum of the bullet

$\implies{P_b=m_b \times v_b}$

$\implies{P_b=0.01 \times 500}$

$\implies{P_b=5 \frac{kgm}{s} }$

Force acting on the car

= total no of bullets fired per sec × momentum of the bullet

$\implies{F_c = n \times P_b}$

$\implies{F_c = 10 \frac{1}{s} \times 5 \frac{kgm}{s} }$

$\implies{F_c = 50 \frac{kgm}{ {s}^{2} } }$

$\boxed{ \red{F_c = 50N}}$

Answer :

• The average thrust on the system is 50 N