Question

A mass 'm' moves with a velocity v and collides in-elastically with another identical mass. After collision the $1^{st}$ mass moves with velocity $\frac{v}{\sqrt{3}}$ in a direction perpendicular to the initial direction of motion. Find the speed of the $2^{nd}$ mass after collision.

• A. $\frac{2v}{\sqrt{3}}$
• B. $v$
• C. $\frac{v}{\sqrt{3}}$
• D. $\sqrt{3}v$

Answer 1

The correct option is A $\frac{2v}{\sqrt{3}}$

By momentom conservation velocity of other mass is

$u=v\hat{i}+\frac{v}{\sqrt{3}}\hat{i}\left|u\right|=\sqrt{v^2+\frac{v^2}{3}}=\frac{2v}{\sqrt{3}}$