Question

A body of mass m moving with a speed v suffers an inelastic collision with another body of M at rest and sticks to it, the ratio of the final kinetic energy of the system to the initial kinetic energy is

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Apply conservation of momentum to find the speed of system after collision
Initial $KE=\frac{1}{2}m{v}^2.FinalKE=\frac{1}{2}(m+M)V^2$. Therefore,
$\frac{FinalKE}{InitialKE}=\left(\frac{m+M}{m}\right)\frac{V^2}{v^2}=\frac{m}{m+M}$
Hence the correct choice is (a).