AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), 2024: Question 5
14 marks · Standard Demand difficulty · Extended Answer
Evaluate tyre safety using braking distance data from a bar chart and calculate braking distance using the work done equation.
Practise this questionQuestion
Question text
05 The stopping distance of a car depends on the thinking distance and the
braking distance.
05.1 Which of the following affects the thinking distance?
[1 mark]
Tick ( ) one box.
Condition of the brakes
Icy road conditions
Reaction time of the driver
A car manufacturer tested three different types of tyre which were fitted to three
identical cars.
This is the method used.
1. Drive the car along a road.
2. Apply the brakes until the car stops.
3. Measure the distance travelled while braking.
4. Repeat steps 1 to 3 for each car when the road is dry and when the road
is wet.
05.2 The brakes were applied with the same force for each test.
Give one other variable that should have been kept the same for each test.
[1 mark]
Figure 10 shows the results.
Figure 10
05.3 The manufacturer wants to put the safest tyres on a new car.
Evaluate the safety of each type of tyre.
Use data from Figure 10.
[6 marks]
When the brakes are applied, a force does work to stop the car.
Use the Physics Equations Sheet to answer questions 05.4 and 05.5.
05.4 Write down the equation that links distance (s), force (F) and work done (W).
[1 mark]
05.5 The braking force acting on a car is 6000 N.
The work done to stop the car is 300 000 J.
*21* Calculate the braking distance of the car.
[3 marks]
Braking distance = m
05.6 Explain how the force applied by the brakes affects the braking distance of the car.
[2 marks]
Mark scheme
Show the mark scheme
Question 5
AO /
Question Answers Extra information Mark
Spec. Ref.
05.1 reaction time of the driver 1 AO1
6.5.4.3.1
AO /
Spec. Ref.
05.2 (initial) speed allow section of road used 1 AO3
6.5.4.3.3
– ignore condition of road without– –
further qualification
AO /
Question Answers Mark
Spec. Ref.
05.3 Level 3: A judgement, strongly linked and logically supported by a 5–6
AO3
sufficient range of correct reasons, is given.
Level 2: Some logically linked reasons are given. There may also 3–4 AO3
be a simple judgement.
Level 1: Relevant points are made. They are not logically linked. 1–2 AO2
No relevant content 0
6.5.4.3.3
Indicative content
• tyre A braking distance is 30 m on dry road and 31 m on wet
road
• tyre A has the shortest braking distance on wet road
• tyre B braking distance is 42 m on dry road and 43 m on wet
road
• tyre B has the longest braking distance on both wet and dry road
• tyre C braking distance is 29 m on dry road and 40 m on wet
road
• tyre C has the shortest braking distance on dry road
• the difference between braking distance on wet and dry roads for
tyre A and tyre B is 1m
• the difference between braking distance on wet and dry roads for
tyre C is 11m
Judgements
• the shorter the braking distance the safer the tyre
• tyre A is 1 m longer on dry road, but is 9 m shorter on wet road
than tyre C
14 • tyre A has the shortest combined / average braking distance
• overall tyre A is the safest
• tyre C is safest on a dry road
• tyre B is the least safe tyre
• the manufacturer should not choose tyre B
allow use of stopping distance for braking distance throughout– – –
AO /
Spec. Ref.
05.4 work done = force × distance 1 AO1
6.5.2
or
W = Fs
AO /
Spec. Ref.
05.5 300 000 = 6000 × s 1 AO2
6.5.2
300 000 1
s =
6000
s = 50 (m) 1
AO /
Spec. Ref.
05.6 the greater the force the shorter 1 AO2
the braking distance 6.5.4.3.4
6.5.4.2.2
(because) deceleration will be 1
greater
or
(because) the work done to stop
the car will be the same
Total Question 5 14
How to answer it
Stopping Distances and Braking Forces
What this question tests
This question assesses your understanding of stopping distances (thinking vs. braking), experimental variables, data evaluation from bar charts, and the relationship between work done, force, and distance.
Factors Affecting Thinking Distance
Correct Answer
- Reaction time of the driver
Key Knowledge
Thinking Distance is the distance travelled during the driver's reaction time. It is affected by tiredness, drugs, alcohol, or distractions.
Common Error
Don't confuse thinking distance with braking distance! Road conditions (ice/wet) and brake quality only affect the braking distance once the pedal is pressed.
Control Variables
Correct Answer
- (Initial) speed of the car
Exam Technique
When asked for a variable to keep the same, think about what would make the test "unfair." If one car was going faster than the others, its braking distance would naturally be longer regardless of the tyres.
Evaluating Tyre Safety (6 Marks)
Analysis of Figure 10
Data Breakdown
- Tyre A: 30m (dry), 31m (wet). Very consistent; only 1m difference. Shortest distance on wet roads.
- Tyre B: 42m (dry), 43m (wet). Longest braking distances overall.
- Tyre C: 29m (dry), 40m (wet). Shortest on dry roads, but a huge 11m increase when wet.
How to get 6 Marks
To reach Level 3 (5-6 marks), you must make a judgement and support it with data for all three tyres.
- State that Tyre A is the safest overall.
- Explain why: It has the shortest braking distance in the wet and is the most consistent.
- Compare with C: While C is slightly better in the dry (by 1m), it is much worse in the wet (by 9m).
- Dismiss B: It is the least safe because it has the longest distances in all conditions.
The Verdict
The manufacturer should choose Tyre A. Safety is most critical in poor conditions (wet roads), where Tyre A outperforms the others significantly.
Calculating Braking Distance
05.4: The Equation
work done = force × distance
Or: W = Fs
05.5: Step-by-Step Calculation
Given: Force (F) = 6000 N, Work Done (W) = 300,000 J
- Rearrange the formula: distance = work done ÷ force
- Substitute the values: distance = 300,000 ÷ 6000
- Solve: distance = 50 m
Calculation Trap
Always check your zeros! A common mistake is losing a zero during division.
300,000 / 6,000 is the same as 300 / 6 .
Force and Distance Relationship
The Explanation
The greater the force applied by the brakes, the shorter the braking distance.
Reason: A greater force causes a greater deceleration (the car slows down faster).
Examiner Insight
You can also explain this using energy: For a fixed amount of kinetic energy (work to be done), if you increase the Force, the Distance must decrease to keep the total Work Done the same ( W = Fs ).
Topics
Physics · P5: Forces
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Foundation), 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.