What does the principle of "conservation of momentum" state?

The principle of "conservation of momentum" states that in a closed system, where no external forces act on it, the total momentum remains constant. This means that the sum of the momentum of all objects in that system before an event (like a collision or an explosion) will be equal to the sum of the momentum of those objects after the event. This principle is a fundamental concept in physics and is crucial in analyzing the outcomes of collisions and interactions between bodies.

When we refer to a closed system, it indicates that the only forces acting are internal to that system, thus not affecting the total momentum. The preservation of momentum is a cornerstone of both classical mechanics and many areas of physics, as it helps in predicting the motion of objects after interactions.

The other choices do not adequately describe the principle. While balanced forces might affect the individual motions of objects, they don’t fundamentally define the conservation of momentum. The assertion that all momentum is lost in collisions is incorrect as momentum is conserved in elastic collisions, while kinetic energy may not be. Lastly, momentum is not necessarily increased when energy is applied; rather, it changes based on the interactions and does not always correlate directly with energy transfer.