A machine gun of mass $10 \mathrm{~kg}$ fires $20 \mathrm{~g}$ bullets at the rate of 180 bullets per minute with a speed of $100 \mathrm{~m} \mathrm{~s}^{-1}$ each. The recoil velocity of the gun is
Solution
<p>Momentum of bullets per unit time</p>
<p>$= {{180 \times {{20} \over {1000}} \times 100} \over {60}}$ kg m/s$^2$</p>
<p>= 6 N</p>
<p>$\Rightarrow$ Force on gun = 6 N</p>
<p>We cannot calculate recoil velocity with the given data.</p>
<p>If we consider recoil velocity at $t = 1$ s, then</p>
<p>${V_{\mathrm{recoil}}} = u + at$</p>
<p>$= 0 + {6 \over {10}} \times 1$ = 0.6 m/s</p>
About this question
Subject: Physics · Chapter: Rotational Motion · Topic: Centre of Mass
This question is part of PrepWiser's free JEE Main question bank. 158 more solved questions on Rotational Motion are available — start with the harder ones if your accuracy is >70%.