Question:
Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Body 'P' having mass M moving with speed 'u' has head-on collision elastically with another body ' $Q$ ' having mass ' $m$ ' initially at rest. If $\$ m<$ Reason $R$ : During elastic collision, the momentum and kinetic energy are both conserved. In the light of the above statements, choose the most appropriate answer from the options given below:
Correct Option: 4,
Solution:
(4)
$m< $e=\frac{V_{2}-V_{1}}{u_{1}-u_{2}}$ For elastic collision $\rightarrow \mathrm{e}=1$ $1=\frac{v_{2}-u}{u-0}$ $\mathrm{u}=\mathrm{v}_{2}-\mathrm{u}$ $v_{2}=2 u$ In elastic collision kinetic energy \& momentum are conserved.