Conservation of momentum

What is conservation of momentum?

The principle of conservation of momentum states that the total momentum of an isolated system remains constant, provided no external forces act. For two colliding objects: m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂. The principle applies to all collisions; kinetic energy is only conserved in elastic collisions. A-Level Physics also examines impulse: F·Δt = Δp (change in momentum), and 2D momentum problems where vectors must be resolved into components.