Question

A particle of mass m moving with a velocity v makes a head on elastic collision with another particle of the same mass initially at rest. The velocity of the first particle after collision is

• A. $v$
• B. $v/2$
• C. $2v$
• D. $0$

Answer 1

The correct option is D $0$

Using linear momentum conservation:
$m(v_1+v_2)=mv$.............(2)

and $\frac{v_2-v_1}{-v}=-1$

$v_2=v+v_1$............(1)

Put (1) in (2):
$\Rightarrow v_1=0$ and $v_2=v$