Kinetic energy changes in collisions

[Jacob Aron]

Is the coefficient of restitution of two particles a measure of the percentage of kinetic energy retained after a collision? My textbooks and Google are no help. If it isn't, what is it a percentage of?

 

[StephenPrivitera]

I've come to love this site. You will too.
http://scienceworld.wolfram.com/physics/CoefficientofRestitution.html

 

[M98Ranger]

The coefficient of restitution (COR) is not a measure of the percentage of kinetic energy retained after a collision. It is a measure of the ratio of the relative velocities of two particles before and after a collision.

In other words, the COR is a measure of the elasticity of a collision. A COR of 1 indicates a perfectly elastic collision, where the two particles bounce off each other with no loss of kinetic energy. A COR of 0 indicates a perfectly inelastic collision, where the two particles stick together after the collision and all kinetic energy is lost.

The COR is not a percentage, but rather a decimal or fraction. For example, a COR of 0.5 means that the relative velocity after the collision is half of the relative velocity before the collision.

To calculate the percentage of kinetic energy retained after a collision, you would need to know the masses and velocities of the particles before and after the collision. This can be calculated using the conservation of momentum and the conservation of kinetic energy equations.

In summary, the coefficient of restitution is not a measure of the percentage of kinetic energy retained after a collision, but rather a measure of the elasticity of the collision. The percentage of kinetic energy retained can be calculated using the conservation laws.