A machine gun fires a bullet of mass $40 \mathrm{~g}$ with a velocity $1200 \mathrm{~ms}^{-1}$. The man…
A machine gun fires a bullet of mass $40 \mathrm{~g}$ with a velocity $1200 \mathrm{~ms}^{-1}$. The man holding it can exert a maximum force of $144 \mathrm{~N}$ on the gun. How many bullets can he fire per second at the most?
one
four
two
three
Solution
Change in momentum for each bullet fired is
$
=\frac{40}{1000} \times 1200=48 \mathrm{~N}
$
If a bullet fired exerts a force of $48 \mathrm{~N}$ on man's hand so $\rho$ man can exert maximum force of $144 \mathrm{~N}$, number of bullets that can be fired $=144 / 48=3$ bullets