MCQ
The first ball of mass $m$ moving with the velocity $v$ collides head on with the second ball of mass $m$ at rest. If the coefficient of restitution is $e$, then the ratio of the velocities of the first and the second ball after the collision is:
- ✓$\frac{1-\text{ e}}{1+\text{ e}}$
- B$\frac{1+\text{e}}{1-\text{e}}$
- C$\frac{1+ \text{ e}}{2}$
- D$\frac{1-\text{ e}}{2}$

