An elastic collision is a type of collision where both momentum and kinetic energy are conserved. Imagine a scenario where two objects collide with each other and then move apart again without any loss of energy. This is an example of an elastic collision. During an elastic collision, the total momentum before the collision is equal to the total momentum after the collision.

For instance, let's consider a game of billiards. When the cue ball strikes a stationary ball on the pool table, the momentum of the cue ball is transferred to the other ball. However, both balls continue to move after the collision, and their total momentum remains the same. This is because the momentum lost by the cue ball is gained by the other ball, leading to a conservation of momentum.

To calculate the velocities before and after an elastic collision, we can use the principle of conservation of momentum. According to this principle, the total momentum before the collision is equal to the total momentum after the collision. This allows us to set up equations to solve for the velocities of the objects involved. These equations are derived from the masses and initial velocities of the objects.

In summary, elastic collisions are those in which both momentum and kinetic energy are conserved. Examples like billiards help us understand how momentum can be transferred between objects during a collision and still remain conserved. By applying the principle of conservation of momentum, we can calculate the velocities of objects before and after an elastic collision, allowing us to further analyze and understand the dynamics of such scenarios.