Momentum (p): The product of mass and velocity. p = mv. Unit: kg m/s. Momentum is a vector quantity — direction matters.
Conservation of momentum: In a closed system, the total momentum before an event equals the total momentum after. Total momentum does not change.
Closed system: A system with no net external forces acting on it, so total momentum is conserved.
Elastic collision: A collision where both momentum AND kinetic energy are conserved. Objects bounce apart.
Inelastic collision: A collision where momentum is conserved but kinetic energy is NOT (some converted to heat/sound). Objects may stick together.
This definitions covers Key Definitions within Momentum for GCSE Physics. Revise Momentum in Forces for GCSE Physics with 15 exam-style questions and 6 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Practice questions for Momentum
What is the equation for momentum?
Explain what is meant by saying momentum is a vector quantity.