Question

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 be fire per second at the most?

Answer 1

Correct Answer - `3 bullets//sec` .
Here, `m = 40 g = 40 xx 10^(-3)kg`
`upsilon = 1200m//s, F = 144 N, n = ?`
As F = rate of change of momentum of bullets
`:. F = nm upsilon`
`n = (F)/(m upsilon) = (144)/(40 xx 10^(-3) xx 1200) = 3` bullets//sec.