Stopping Distances and Reaction Time

Question 1

What is meant by the ‘braking distance’ of a car?

Answer 1

The distances the car travels under the braking force/once the brakes are applied

Question 2

True or false? Braking distance is the same as stopping distance

Answer 2

False

Stopping distance is equal to thinking distance plus braking distance

Question 3

What’s the typical range for human reaction times in a ruler drop experiment? Give two factors that can affect this range

Answer 3

0.2s - 0.6 s

You could have given factors including drugs, distractions, alcohol, tiredness

Question 4

State and explain the effect that worn brakes will have on the braking distance of a lorry

Answer 4

The braking distance of the lorry will increase because the force applied by the brakes is reduced when they are worn.

Question 5

How does rain increase the braking distance of a vehicle?

Answer 5

Rain will leave water on the road surface which reduces friction. Reduced friction increases the chance of the vehicle skidding when braking, which will increase the distance the vehicle travels before coming to rest

Question 6

Briefly describe a method you could use to measure a person’s reaction time

Answer 6

You could use a computer-based test where the person clicks a mouse in response to a stimulus. Alternatively, hang a ruler between the person’s thumb and forefinger. Drop the ruler without warning and record the measurement at the point where they catch the ruler. You can then work out their reaction time from the distance the ruler fell.

Question 7

Scientists have found that tiredness increases a driver’s reaction time. Explain the implication this has for road safety

Answer 7

Increased reaction time increases thinking distance, which increases stopping distance. Increased stopping distance means a higher risk of accidents. So tiredness in driver will have negative effect on road safety