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 $m<< M,$ body '$Q$' will have a maximum speed equal to '$2u$' after collision
Reason R : During elastic collision, the momentum and kinetic energy are both conservedIn the light of the above statements, choose the most appropriate answer from the options given below :

• A. $A$ is not correct but $R$ is correct.
• B. Both $A$ and $R$ are correct but $R$ is NOT the correct explanation of $A$
• C. Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$
• D. $A$ is correct but $R$ is not correct.

Answer 1

Answer: (C)

For e $=1$ & second body at rest
$V _{2}=\frac{2 m _{1} u _{1}}{ m _{1}+ m _{2}}=\frac{2 u ( M )}{ M + m } \simeq 2 u$
Since $M \gg m$