AQA GCSE Physics Paper 2 Practice Exam 2026 - Free AQA GCSE Physics Practice Questions and Study Guide

In a closed system, the principle of conservation of momentum states that the total momentum remains constant both before and after a collision. This means that the sum of the momenta of all objects involved in the collision does not change as long as no external forces act on the system.

When a collision occurs, the momenta of the individual objects may change, but the overall momentum, calculated by adding all the individual momenta together, will remain the same. This is fundamental to understanding interactions in physics, particularly in analyzing the outcomes of collisions, whether they are elastic or inelastic.

The total momentum before the collision is equal to the total momentum after the collision, demonstrating that the momentum carried into the system by the objects is conserved. This principle is pivotal in various applications in physics, from simple mechanics problems to more complex systems involving multiple interacting bodies.