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 500m/ s with respect to the car . The number of bullets fired per second is ten. The average thrust on the system is ??

Answer 1

u = velocity of bullet = 500m/sec.

dm / dt = Mass thrown per second by the machine gun = Mass of bullet × Number of bullet fired per second

= 10 g×10 bullet/sec

= 100 g/sec = 0.1 kg/sec

∴ Thrust = udm/dt= 500×0.1=50 N