This key facts covers Elastic vs Inelastic Collisions within Impulse & Collisions for GCSE Physics. Revise Impulse & Collisions in Forces for GCSE Physics with 13 exam-style questions and 10 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 6 of 7 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
💥 Elastic vs Inelastic Collisions
Elastic collision:
- Momentum is conserved ✓
- Kinetic energy is ALSO conserved ✓
- Objects bounce apart
- Example: Newton's cradle (approximately), snooker balls
Inelastic collision:
- Momentum is conserved ✓
- Kinetic energy is NOT conserved ✗ (some converted to heat/sound)
- Objects may stick together or deform
- Example: car crashes, catching a ball
💡 Key point: Momentum is ALWAYS conserved in collisions (closed system). Kinetic energy is only conserved in perfectly elastic collisions (rare in real life).
Practice questions for Impulse & Collisions
Which equation correctly defines impulse?
Explain how an airbag reduces the risk of injury to a driver in a collision.