The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

Law of conservation says that the total momentum of any closed and isolated system cannot change.

Law of conservation of momentum implies that initial momentum is equal to the final momentum. This law is true for an isolated system. Isolated system means net external force acting on it is equal to zero.

Momentum is the product of mass and velocity with which an object is moving.

i. e. p = m v