Question

Define Law of Conservation Of Momentum.

Answer 1

For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

Answer 2

The total momentum of a system remains constant if no external force acts in the system.
                                      (or)
When two or more bodies interact with one another,the vector sum of their linear momenta remains constant.