What does the conservation of momentum state?

The conservation of momentum states that in a closed system, the total momentum remains constant over time, provided that no external forces are acting on it. This principle is a fundamental concept in physics, particularly in the study of collisions and interactions between objects.

When two or more objects collide or interact, the momentum before the interaction is equal to the momentum after the interaction. This means that any momentum lost by one object will be gained by another, leading to the overall momentum of the system being conserved. This principle is crucial for analyzing both elastic and inelastic collisions, where energies and directions of the involved objects can change, but the total momentum stays constant.

Understanding this principle is essential for solving problems related to physics and dynamics, offering insight into how objects behave during interactions. The other choices do not align with this fundamental principle; they suggest incorrect scenarios regarding momentum in a system.