An elastic collision is a collision in which there is no net loss in kinetic energy in the system as a result of the collision. Both momentum and kinetic energy are conserved quantities in elastic collisions. Suppose two similar trolleys are traveling toward each other with equal speed.

How do you know if a collision is elastic?

If objects stick together, then a collision is perfectly inelastic. When objects don't stick together, we can figure out the type of collision by finding the initial kinetic energy and comparing it with the final kinetic energy. If the kinetic energy is the same, then the collision is elastic.

How do you find if a collision is elastic or inelastic?

If the total kinetic energy before the collision equals the total kinetic energy after the collision, the collision is elastic. Otherwise, it isn't elastic.