During a crash test, a car travelling at high speed comes to a sudden stop. Explain how an airbag reduces the risk of serious injury to the driver during this type of collision.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Modern cars are fitted with airbags that inflate very rapidly when sensors detect a sudden deceleration.
Model answer (4 marks)
The airbag inflates rapidly and forms a cushion between the driver and the steering wheel or dashboard.
When the car stops suddenly the airbag increases the time over which the driver decelerates.
A longer stopping time reduces the force acting on the driver for the same change in momentum (F=Δp/Δt).
A smaller force means a lower risk of serious injury such as head, chest or internal injuries.
When the car stops suddenly the airbag increases the time over which the driver decelerates.
A longer stopping time reduces the force acting on the driver for the same change in momentum (F=Δp/Δt).
A smaller force means a lower risk of serious injury such as head, chest or internal injuries.
Examiner tips
- Use the word "inflates" and mention the cushion between driver and steering wheel/dashboard.
- Explain the increase in stopping time and link it to force via F=Δp/Δt.
- Show that a lower force reduces injury risk – mention head, chest or internal injuries.
Common mistakes
- Failing to mention the cushion between driver and steering wheel/dashboard.
- Confusing force with acceleration – not showing the Δp/Δt relationship.
- Leaving out the link between reduced force and lower injury risk.
Mark scheme (4 marks)
- The airbag inflates and acts as a cushion between the driver and the steering wheel / dashboard
- The airbag increases the time over which the driver decelerates / comes to a stop
- A longer stopping time means the force acting on the driver is reduced (for the same change in momentum)
- A smaller force on the driver means less risk of serious injury / internal injuries / head or chest injuries
Key terms in this question
Related
- All Eduqas GCSE Physics revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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