question_answer

A machine gun fires a bullet of mass 40gm with a velocity of 1200 m/s. The man holding it can exert a force of 144 N on the gun. How many bullets can he fire per second at the most?

Answer:

\[m=40\,\,g=\frac{40}{1000}kg=\frac{1}{25}kg,\,\,u=0\] \[v=1200\,\,m/s\] \[F=144\,Nn=?t=1s\] \[F=n\,\,ma=n\,\,m\left( \frac{v-u}{t} \right)\] \[\Rightarrow 144=n\left( \frac{1}{25} \right)\left( \frac{1200-0}{1} \right)\] \[\Rightarrow 144=\frac{n}{25}\times 1200\] \[n=\frac{144\times 25}{1200}=3\] Hence n = 3.