conservation of momentum

Conservation of momentum is a fundamental principle in physics stating that the total momentum of a closed system remains constant if no external forces act on it. Momentum, which is the product of an object's mass and its velocity, can be thought of as a measure of how hard it is to stop an object. In simple terms, when two objects collide, the momentum before the collision equals the momentum after the collision. This principle helps us understand various phenomena, from car crashes to celestial mechanics, ensuring the predictable behavior of moving objects in an isolated environment.