Conservation of momentum is a fundamental principle in physics that states that the total momentum of a closed system remains constant unless acted upon by external forces. It is based on Isaac Newton's third law of motion, which states that for every action, there is an equal and opposite reaction.

To understand conservation of momentum, let's consider a simple example. Imagine a car collision on an ice rink. Before the collision, both cars have their own momenta, which can be calculated as the product of their respective masses and velocities. Once the collision occurs, the total momentum of the two cars combined remains the same. This means that if one car loses momentum, the other car gains an equal amount of momentum to ensure overall conservation.

Conservation of momentum is significant in physics because it allows us to predict and analyze the motion of objects in various scenarios. By understanding this principle, we can explain the behavior of objects in collisions, explosions, and other interactions.