🎯 Common Question Types:
- Calculate thinking distance (speed × reaction time) — 1-2 marks
- State TWO factors affecting braking distance — 2 marks
- Explain why speeding is dangerous using physics (braking ∝ v²) — 3 marks
- Describe the effect of alcohol on stopping distance — 2-3 marks
📝 Key Command Words:
- State: Just name the factor — no explanation needed
- Explain: State the factor → link to reaction time or friction → link to distance
- Calculate: Show thinking distance = speed × reaction time
- Describe: Mention all three stages (see hazard → react → brake → stop)
⚠️ Common Mistakes to Avoid:
- Saying "stopping distance doubles when speed doubles" — it more than doubles
- Mixing up which factors affect thinking vs braking distance
- Forgetting that wet roads affect braking distance, NOT thinking distance
- Not linking braking distance to kinetic energy in "explain" questions
Quick Check: A car doubles its speed from 10 m/s to 20 m/s. What happens to: (a) thinking distance and (b) braking distance?
(a) Thinking distance doubles (proportional to v). (b) Braking distance quadruples (proportional to v²). This is because kinetic energy = ½mv², so four times the energy must be transferred by the brakes.
Quick Check: Give TWO factors that affect braking distance but NOT thinking distance.
Any two from: condition of tyres (worn tyres = less grip), road surface (wet/icy roads = less friction), condition of brakes (worn brakes = less braking force), mass of vehicle (heavier = more KE to transfer). Remember: thinking distance is about the DRIVER, braking distance is about the CAR and ROAD.
This exam tips covers Exam Tips for Stopping Distances within Stopping Distances for GCSE Physics. Revise Stopping Distances in Forces for GCSE Physics with 15 exam-style questions and 5 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 11 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Practice questions for Stopping Distances
What is the correct definition of stopping distance?
Explain why a car travelling at higher speed has a greater braking distance than a car travelling at lower speed, assuming the same braking force.