A machine gun fires a bullet of mass 40 g with a velocity 1200 ms-1. The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most?

u = velocity of bulletdmdt = Mass fired per second by the gundmdt =  Mass of bullet (mB) ×Bullets fired per sec (N)Maximum force that man can exert F = u(dmdt)F = u × mB×N⇒ N = FmB×u = 14440 ×10-3×1200 = 3