Teacher's notes and answers to questions in the book - Hodder Plus ...

WJEC GCSE Additional Science Teacher’s Notes
18
Cars, the Highway Code
and collisions
_ Total stopping distance of a vehicle (pages 200–3)___
Questions
1. For a vehicle, what is the:
a thinking distance
The distance that the vehicle travels whilst the driver sees the hazard, thinks about braking
and then actually reacts to put the brakes on.
b braking distance
The distance that the vehicle moves while the brakes are being applied.
c
total stopping distance
total stopping distance = thinking distance + braking distance
2. State and explain two factors that affect the thinking distance of a stopping car.
Velocity of car, reaction time of the driver, driver distractions, use of mobile phone/radio/mp3/
Sat Nav, being drunk or under the influence of drugs, etc. Each factor needs a reasonable
explanation.
3. Do you think that smoking whilst driving a car affects the total stopping distance Explain your answer.
Smoking does affect the total stopping distance because it is a driver distraction, and the driver
may be holding the cigarette when something happens not have that hand on the wheel.
4. Increased tyre tread greatly reduces the braking distance of a car. Why do you think that cars are not all
fitted with thick, chunky, off-road tyres with huge treads
Thick, chunky, off-road tyres with huge treads increase the friction between the tyre and the
road. Increased friction will mean that the engine has to do more work, hence fuel consumption
will increase. The ride quality will also be worse as the noise will be higher and the ride will be
more uncomfortable.
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