New Stopping Distance Video and Resources
Stopping distance is a core topic in GCSE Physics and IGCSE Physics, and it appears frequently in exams. Many students lose marks on this topic because of vague answers, confusion between key terms, or weak exam technique.
In this guide, I’ll clearly explain:
- What stopping distance is
- The difference between thinking distance and braking distance
- The factors that affect each
- Common exam mistakes to avoid
This page works alongside my YouTube video on stopping distance, which explains these ideas step by step. The video can be found here: https://youtu.be/k9DW0MY_fL4
Practice questions and answers on stopping distances, along with other Forces topics can be found here: https://videoplatoacademy.com/gcseresources-forces/
What Is Stopping Distance?
The stopping distance of a vehicle is the total distance travelled from the moment a driver sees a hazard to the moment the vehicle comes to a complete stop.
In GCSE and IGCSE Physics, stopping distance is always split into two parts:
Stopping distance = thinking distance + braking distance
Understanding the difference between these two distances is essential for exam success.
Thinking Distance Explained
The thinking distance is the distance travelled by the car while the driver is reacting.
It:
- Starts when the driver sees the hazard
- Ends when the driver presses the brake pedal
Factors That Affect Thinking Distance
Thinking distance depends on:
- The speed of the car
- The reaction time of the driver
The key equation you must know is:
Thinking distance = speed × reaction time
Anything that increases a driver’s reaction time will increase the thinking distance, including:
- Tiredness
- Alcohol
- Drugs
- Using a mobile phone
- Lack of concentration
⚠️ Exam tip:
Poor visibility (fog, darkness, heavy rain) does not directly increase thinking distance. Thinking distance only begins once the hazard has been seen.
Example Thinking Distance Calculation
A car is travelling at 12 m/s.
The driver’s reaction time is 0.5 seconds.
Thinking distance = speed x reaction time = 12 × 0.5 = 6 m
This shows how far the car travels before braking even begins.
More practice questions can be found here: https://videoplatoacademy.com/gcseresources-forces/
Braking Distance Explained
The braking distance is the distance travelled from when the brakes are applied to when the car stops completely.
At this point, stopping the car is no longer controlled by the driver — it depends on:
- Friction
- Speed
Factors That Increase Braking Distance
You must be specific in exams. Correct answers include:
- Worn tyres
- Poorly maintained brakes
- Water, ice, oil or mud on the road
- Uneven road surfaces
- High speed
❌ Vague answers such as “bad weather” or “poor road conditions” often lose marks.
Why Speed Is So Important
At speeds above 20 mph, the braking distance is usually greater than the thinking distance. This means that even highly skilled drivers cannot stop quickly if they are travelling too fast.
A crucial exam fact to remember:
- Doubling speed doubles thinking distance
- Doubling speed quadruples braking distance
This is because kinetic energy increases with the square of the speed.
Common Exam Mistakes to Avoid
Students often lose marks by:
- Confusing reaction time with thinking distance
- Giving vague factors instead of specific ones
- Forgetting the thinking distance equation
- Assuming driver skill reduces braking distance at high speeds
Examiners reward clear definitions, correct equations, and specific factors.
GCSE & IGCSE Stopping Distance Revision Help
If you’d like more help with stopping distance and other Physics topics:
- 🎥 Watch my GCSE & IGCSE Physics videos on YouTube
- 📘 Access free exam questions and resources at
👉 https://www.videoplatoacademy.com
I also offer affordable 1-to-1 GCSE and IGCSE Physics tuition, focused on building confidence and exam technique.
Find out about my online or in person Physics lessons here: https://videoplatoacademy.com/lessons/
Final Exam Tip
Remember:
Stopping distance = thinking distance + braking distance
Master the definitions, learn the equations, and always be specific in your answers.
