Question

A particle of mass mi moves with velocity $v_{1}$ and collides with another particle at rest of equal mass. The velocity of the second panicle after the elastic collision is

• A. $ 2v_{1}$
• B. $v_{1}$
• C. $ -v_{1}$
• D. 0

Answer 1

Answer: (B)

Given, mass $m_{1}=m_{2}=m$
and velocity $u_{1}=v_{2}$
For elastic collision
$v_{2}\left(\frac{m_{2}-m_{1}}{m_{1}+m_{2}} m_{1}+m_{2}\right) = v_{2} +\frac{2 m_{1} u_{1}}{m_{1}+m_{2}}$
After putting given values we will get
$v_{2}=\frac{2 m_{1} v_{1}}{2 m_{1}}$
$v_{2}=v_{1}$