Mass*Velocity

Vector

Important in determining the outcome of collisions between two objects of mass as well as in determining the ease with which one can stop or change direction of travel when velocity is present.

Momentum of a system must remain the same regardless of the cirumstances which might occur over time including collisions. All momentum present prior to a time of observation is present immediately after the observation.

Mbefore=Mafter

M1+M2=M1+M2

Pool Balls=example