ForcesKey Facts

Elastic vs Inelastic Collisions

Part of Impulse & CollisionsGCSE Physics

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. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 4 of 4 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 4 of 4

Practice

13 questions

Recall

10 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).

Keep building this topic

Read this section alongside the surrounding pages in Impulse & Collisions. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Impulse & Collisions

Which equation correctly defines impulse?

  • A. impulse = force / time
  • B. impulse = force x time
  • C. impulse = mass x acceleration
  • D. impulse = mass x velocity
1 markfoundation

Explain how an airbag reduces the risk of injury to a driver in a collision.

3 marksstandard

Quick Recall Flashcards

Understanding Impulse
Impulse = Change in momentum (Δp = mΔv) — measured in kg m/s
Understanding Impulse
Impulse = Force × time (F × t) — measured in N s

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