The conservation of momentum is a fundamental principle in physics that states that the total momentum of a closed system remains constant before and after an interaction or event occurs. This principle holds true unless external forces are acting on the system. To understand the concept of conservation of momentum, let's consider a few examples.

Collision between two objects: When two objects collide, the total momentum before the collision is equal to the total momentum after the collision, provided no external forces are involved. This means that the combined momentum of the objects remains constant.

Explosion: In an explosion, a single object breaks apart into multiple fragments. Despite the fragmentation, the total momentum of the system remains constant because there are no external forces acting on it.

Rocket propulsion: When a rocket propels itself forward, it expels exhaust gases backward. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. The momentum of the expelled gases in one direction is equal and opposite to the momentum of the rocket in the opposite direction, resulting in a net momentum of zero for the system.

In each of these examples, the total momentum of the system remains the same before and after the event, demonstrating the conservation of momentum. This principle allows for the analysis and prediction of various physical phenomena, such as the motion of objects in collisions and explosions.