Q 11-05-013NEETJEE MainEAMCET 2007 (Medical)Medium
A sphere of mass $m$ moving with constant velocity $u$ collides with another stationary sphere of the same mass. If $e$ is the coefficient of restitution, the ratio of the final velocities of the first and second sphere is
Answer: (B) $\dfrac{1 - e}{1 + e}$
Concept. Momentum and restitution equations for equal masses.
Step 1. Equations. $v_1 + v_2 = u$, $v_2 - v_1 = eu$.
Step 2. Ratio. $\dfrac{v_1}{v_2} = \dfrac{1 - e}{1 + e}$.
Answer. $\dfrac{1 - e}{1 + e}$ (Option B).
Solution by Sreeraj P, M.Sc Physics