In an elastic collision, both momentum and kinetic energy are conserved. This means that the total momentum of the system before the collision is equal to the total momentum of the system after the collision, and the total kinetic energy of the system before the collision is equal to the total kinetic energy of the system after the collision.

Elastic collisions are often idealized, as in reality some energy is always lost to heat and sound. However, they can be a useful approximation for many real-world situations.

Some examples of elastic collisions include:

* Two billiard balls colliding with each other

* A tennis ball bouncing off a wall

* A golf ball bouncing off a golf club

Inelastic collision

In an inelastic collision, momentum is conserved, but kinetic energy is not. This means that the total momentum of the system before the collision is equal to the total momentum of the system after the collision, but the total kinetic energy of the system before the collision is not equal to the total kinetic energy of the system after the collision.

Some energy is lost to heat and sound in an inelastic collision. This can happen when the objects involved in the collision deform or stick together.

Some examples of inelastic collisions include:

* A car crash

* A ball of clay hitting a wall

* A golf ball hitting a tree

Comparison of elastic and inelastic collisions

The following table summarizes the key differences between elastic and inelastic collisions:

| Property | Elastic collision | Inelastic collision |

|---|---|---|

| Momentum conservation | Yes | Yes |

| Kinetic energy conservation | Yes | No |

| Objects deform or stick together | No | Yes |

| Examples | Billiard balls colliding, tennis ball bouncing off a wall, golf ball bouncing off a golf club | Car crash, ball of clay hitting a wall, golf ball hitting a tree |