Question

what is conservation of momentum

Answer 1

》It states that the the sum of the momenta before the collision is equal to the sum of the momenta after the collision until there's no external force acts on iy.

Answer 2

❇️Here's your answer:-

Conservation of momentum is a fundamental law of physics which states that the momentum of any body is constant if there are no external forces acting on the system. It is stated in Newton's first law (the law of inertia).
⚫For example:-
In a collision, the momentum change of object 1 is equal to and opposite of the momentum change of object 2. That is, the momentum lost by object 1 is equal to the momentum gained by object 2. In most collisions between two objects, one object slows down and loses momentum while the other object speeds up and gains momentum.