A ball with a mass of 4kg and velocity of 1ms collides with a second ball with a mass of 5kg and velocity of 8ms. If 25% of the kinetic energy is lost, what are the final velocities of the balls?

1 Answer
Mar 28, 2017

Approximately 5.20 meters per second

Explanation:

Kinetic energy formula is E=0.5mvv
m is for mass (kg) and v is for velocity (m/s).
The first ball's kinetic energy is E1=2kgmmss
The second ball's kinetic energy is E2=160kgmmss
Total energy when they collide is E=162kgmmss

However only 75% of this value is saved after collision of these balls. In other words total kinetic energy after collision is 121.5kgmmss

Final mass of these balls 9kg but what is final velocity?

121.5kgmmss=0.59vv

27=vv

5.196=v (as m/s).

This is the answer of the velocity of the final ball (9 kg). It moves similar to the direction of the second ball with a lower speed.