What principle states that momentum is conserved in collisions?

The principle that states that momentum is conserved in collisions is known as the Law of Conservation of Momentum. This law asserts that in a closed system, where no external forces are acting, the total momentum before any interaction (such as a collision) is equal to the total momentum after the interaction.

Momentum is defined as the product of an object's mass and its velocity, and it is a vector quantity, meaning it has both magnitude and direction. In collisions, whether they are elastic (where kinetic energy is also conserved) or inelastic (where kinetic energy is not conserved), the total momentum of the system will remain constant, as long as no external forces interfere.

This principle is foundational for analyzing various physical scenarios, ranging from simple two-object collisions to complex interactions in larger systems, and it plays a critical role in physics and engineering, helping predict the outcomes of collisions and interactions effectively. Understanding momentum conservation allows for the analysis of problems in both classical mechanics and various applications in technology and engineering.