Conservation of momentum
What Conservation of momentum means in Physics A-Level, as defined for AQA, OCR.
Definitions of Conservation of momentum
Exam boards and our study guides word this term in slightly different ways. Learn the version your board uses.
Check what you remember
Read the wording for your board, then hide it and explain Conservation of momentum in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: AQA
The wall and a molecule are treated as an isolated system during the collision, so total momentum is conserved.
For a collision, total momentum before and after is compared to test whether it is conserved.
Momentum is conserved whenever no resultant external force acts.
Also requires a third particle in beta decay.
Topics that use Conservation of momentum
- Molecular kinetic theory model (A-level only) (AQA A-Level)
- Stable and unstable nuclei (AQA A-Level)
- Collisions (OCR A-Level)
- Linear motion (OCR A-Level)
Related terms
- Acceleration due to gravity
- Alpha decay
- Beta-minus decay
- Beta-plus decay
- Binding and saturation of the strong force
- Braking distance
- Brownian motion
- Collisions and resultant forces
Using Conservation of momentum in the exam
Check the command word and mark scheme for your exact question. After comparing your explanation with the reference, use the term in an answer on the linked topic. This practice does not predict an exam mark.
Practise Physics questions
Create a free account to answer exam-style questions on this topic and get feedback on your answers.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge