Question

A bullet is fired from a rifle which recoils after firing. If the energy released in firing is 1500 J, then the kinetic energy of the rifle after firing may be

• A. 1000 J
• B. 750 J
• C. 1200 J
• D. 500 J

Answer 1

The correct option is D 500 J

Initially, friction force is equal to applied force parallel to surface



$\frac{K_{rifle}}{K_{bullet}}=\frac{\frac{p^2}{2M}}{\frac{p^2}{2m}}=\frac{m}{M}<1$

$K_{rifle}<K_{bullet}$

So, the rifle energy will be less than $50\%$ of the total released energy.