Question

A block of mass $m$ moving at a speed $v$ collides with another block of mass $3m$ at rest. If the light block comes to rest after collision, the coefficient of restitution is :

• A. $\frac{1}{3}$
• B. $\frac{1}{6}$
• C. $\frac{1}{2}$
• D. $\frac{1}{4}$

Answer 1

The correct option is A $\frac{1}{3}$

Using momentum conservation
$mv=3m{v}^{\prime }$

$\Rightarrow v^{\prime }=\frac{v}{3}$

$e=\frac{v^{\prime }-0}{v}=\frac{\frac{v}{3}}{v}=\frac{1}{3}$