Question

Which of the following statements is incorrect regarding a partially inelastic collision?

• A. Impulse of reformation is equal to the impulse of deformation.
• B. Momentum remains conserved if other external forces are absent on the colliding object.
• C. Total mechanical energy is not conserved during inelastic collision.
• D. Coefficient of restitution lies in the range $(0<e<1)$

Answer 1

The correct option is A Impulse of reformation is equal to the impulse of deformation.

Coefficient of restitution is defined as the ratio of impulse of reformation and impulse of deformation, for either of the colliding body.
$e=\frac{\text{Impulse of reformation}}{\text{Impulse of deformation}}=\frac{\text{Speed of separation}}{\text{Speed of approach}}$

$\Rightarrow 0<e<1$, hence $\text{Impulse of reformation}$ will not be equal to $\text{Impulse of deformation}$.
Total mechanical energy is not conserved as some part of kinetic energy is converted as elastic potential energy during deformation.
$\therefore$ Option $\left(a\right)$ is incorrect.