During a collision, an object always encounters an impulse and a change in momentum.

During a collision, the impulse which an object experiences is equal to its velocity change.

The velocity change of two respective objects involved in a collision will always be equal.

While individual objects may change their velocity during a collision, the overall or total velocity of the colliding objects is conserved.

In a collision, the two colliding objects could have different acceleration values

Total momentum is always conserved between any two objects involved in a collision

When a moving object collides with a stationary object of identical mass, the stationary object encounters the greater collision force.

Total momentum is conserved only if the collision can be considered isolated from the influence of net external forces.

When a moving object collides with a stationary object of identical mass, the stationary object encounters the greater collision force.

When a moving object collides with a stationary object of identical mass, the stationary object encounters the greater momentum change

Perfectly elastic and perfectly inelastic collisions are the two opposite extremes along a continuum; where a particular collision lies along the continuum is dependent upon the amount kinetic energy which is conserved by the two objects

Most collisions tend to be partially to completely elastic

A moving air track glider collides with a second stationary glider of identical mass. The first glider loses all of its kinetic energy during the collision as the second glider is set in motion with the same original speed as the first glider. Since the first glider lost all of its kinetic energy, this is a perfectly inelastic collision.

The collision between a tennis ball and a tennis racket tends to be more elastic in nature than a collision between a halfback and linebacker in football.