Momentum cannot be created or destroyed during a collision, but it can be transferred between objects. This is known as the law of conservation of momentum. The total momentum of a closed system remains constant, even if the individual momenta of the objects within the system change.

Consider a simple collision between two objects. Before the collision, each object has its own momentum, which is determined by its mass and velocity. When the objects collide, some of the momentum is transferred from one object to the other. The total momentum of the two objects after the collision is the same as the total momentum before the collision.

The law of conservation of momentum is a fundamental principle of physics and has important applications in many areas, such as mechanics, ballistics, and rocketry. It is also used to study the behavior of subatomic particles and the interactions between atoms and molecules.