Law of Conservation of Momentum (Elastic Collisions)

What are elastic collisions?

In Prelim Physics, we analyse quantitatively and predict, using the law of conservation of momentum $\Sigma m \vec{v}_{before} = \Sigma m \vec{v}_{after}$ and, where appropriate, conservation of kinetic energy $\frac{1}{2} m v^{2}_{before} = \frac{1}{2} m v^{2}_{after}$ , the results of interactions in elastic collisions. 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.

The following three videos go over the types of collisions, and the related calculations required to solve questions.