Q. A particle of mass $m$ collides with another stationary particle of mass $M$. If the particle $m$ stops just after collision, the coefficient of restitution of collision is equal to
A) 1
B) $\frac{m}{M}$
C) $\frac{M - m}{M + m}$
D) $\frac{m}{M + m}$
Explanation
(b) As net horizontal force acting on the system is zero, hence momentum must remain conserved. Hence
$mu + 0 = 0 + mv_{2} \Rightarrow v_{2} = \frac{mu}{M}$
As per definition,
$e = - \frac{\left( v_{1} - v_{2} \right)^{\ }}{(u_{2} - u_{1})} = \frac{v_{2} - 0}{o - u} = \frac{v_{2}}{u} = \frac{\frac{mu}{M}}{u} = \frac{m}{M}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.