Q 11-05-044NEETJEE MainMedium
A body of mass $m$ moving with speed $v$ collides with an identical body at rest and sticks to it. The fraction of the initial kinetic energy lost in the collision is
Answer: (C) $\dfrac{1}{2}$
Concept. Momentum gives common speed $\dfrac v2$.
Step 1. Final KE. $\dfrac12(2m)\dfrac{v^2}{4} = \dfrac14mv^2$, half the initial.
Step 2. Fraction lost. $\dfrac12$.
Answer. $\dfrac12$ (Option C).
Solution by Sreeraj P, M.Sc Physics