Conservation of momentum: One-dimensional collisions and explosions using Σp(before) = Σp(after)

What this note covers

1. Where momentum sits in Criterion 6, and the limits that define the question style
2. Momentum: what p = mv actually says
3. The conservation statement and the conditions it needs
4. Collisions in one dimension: the standard set-up
5. Explosions and recoil: the same law read backwards
6. Momentum and kinetic energy are different questions
7. Common problem shapes and how to recognise them from the wording
8. How Section C examines this — and what separates a top answer

8 sections · 12 key terms & formulas · 6 common mistakes