Q. A machine gun fires a steady stream of bullets at the rate of $n$ per minute into a stationary target in which the bullets get beaded. If each bullet has a mass $ma$ and arrive at the target with a velocity $v$, the average force on the target is
A) 60 $mnv$
B) $\frac{60v}{mn}$
C) $\frac{mnv}{60}$
D) $\frac{mv}{60n}$
Explanation
(c) $F = \frac{\mathrm{\Delta}p}{\mathrm{\Delta}t} = v\frac{\mathrm{\Delta}m}{\mathrm{\Delta}t} = v\frac{nm}{t}$
$F = vm\frac{n}{60} = \frac{mvn}{60}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.