A ball X of mass 1 kg travelling at 2 m/s has a head-on collision with an identical ball Y at rest. X stops and Y moves off. Calculate the velocity of Y after the collision.


Here, the mass of the ball X $=m_{X}=1\ kg$

Mass of the ball Y $=m_{Y}=1\ kg$


Before collision:

The velocity of the ball X $=u_{X}=2\  m/s$

The velocity of  the ball Y $=u_{Y}=0$


After collision:

The velocity of the ball X $=v_{X}=0$

The velocity of  the ball Y $=v_{Y}=?$

According to the law of conservation of momentum:

$m_{X}u_{X}+m_{Y}u_{Y}=m_{X}v_{X}+m_{Y}v_{Y}$

Or $1\ kg\times2\ m/s+1\ kg\times0=1\ kg\times0+1\ kg\times v_{Y}$

Or $v_{Y}=2\ m/s$

Therefore, the velocity of the ball Y is $2\ m/s$.

Updated on: 10-Oct-2022

62 Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements