AQA GCSE Combined Science: Trilogy Physics Paper 1 (Foundation), 2023: Question 2
9 marks · Standard Demand difficulty · Short Answer
Analyze energy changes, calculate gravitational potential and kinetic energy, and explain the effect of friction for a person on a zip wire.
Practise this questionQuestion
Question text
02 Figure 3 shows a person using a zip wire to move from a tree to the ground.
Figure 3
As the person moves down the zip wire, the block moves upwards.
02.1 What happens to the gravitational potential energy of the person as the person
accelerates down the zip wire?
[1 mark]
Tick ( ) one box.
Decreases
Stays the same
Increases 9
02.2 What happens to the kinetic energy of the person as the person accelerates down the
zip wire?
[1 mark]
Tick ( ) one box.
Decreases
Stays the same
Increases
02.3 The block is 3.4 m above the ground when the person is at the bottom of the zip wire.
mass of block = 2.5 kg
gravitational field strength = 9.8 N/kg
Calculate the gravitational potential energy of the block.
Use the equation:
gravitational potential energy = mass × gravitational field strength × height
[2 marks]
Gravitational potential energy = J
The trolley is a seat suspended from wheels which can roll along the zip wire.
02.4 When the person reaches the end of the zip wire, the person gets off the trolley.
The block falls downwards pulling the trolley back to the top of the zip wire.
maximum speed of block = 4.8 m/s
mass of block = 2.5 kg
Calculate the maximum kinetic energy of the block.
Use the equation:
kinetic energy = 0.5 × mass × (speed)2
[2 marks]
Maximum kinetic energy = J
02.5 As the trolley moves, work is done against friction.
What is the effect of this?
[1 mark]
Tick ( ) one box.
Some energy is destroyed.
Some energy is transferred to the surroundings.
The total energy of the block and trolley increases.11
02.6 The person oils the wheels on the trolley.
Explain how this will affect the speed of the person down the zip wire.
[2 marks]
Mark scheme
Show the mark scheme
Question 2
AO /
Question Answers Extra information Mark
Spec. Ref.
02.1 decreases 1 AO1
6.1.1.1
AO /
Spec. Ref.
02.2 increases 1 AO 1.1
6.1.1.1
AO /
Spec. Ref.
02.3 Ep = 2.5 × 9.8 × 3.4 1 AO2
6.1.1.1
Ep = 83.3 (J) allow 83 (J) 1 6.1.1.2
AO /
Spec. Ref.
02.4 E = 0.5 × 2.5 × 4.82 1 AO2
k
6.1.1.1
Ek = 28.8 (J) allow 29 (J) 1 6.1.1.2
AO /
Spec. Ref.
02.5 some energy is transferred to 1 AO1
the surroundings 6.1.1.1
– OMBINED SCIENCE: TRILOGY – 1F – 6.1.2.1
AO /
Spec. Ref.
02.6 speed will increase 1 AO1
6.1.2.1
(because work done against) 1
friction decreases
Total Question 2 9
How to answer it
Energy Transfers on a Zip Wire
This question assesses your ability to identify changes in energy stores (Gravitational Potential and Kinetic), perform energy calculations using provided formulas, and understand how friction and lubrication affect the efficiency and speed of a system.
Identifying Energy Changes
Assessing energy stores during motion
Correct Answers
- 02.1: Decreases (GPE)
- 02.2: Increases (KE)
Key Knowledge
- GPE: Depends on height. As the person moves down, height decreases, so GPE decreases.
- KE: Depends on speed. As the person accelerates, speed increases, so KE increases.
Exam Technique
Look for the word "accelerates" in the question. Acceleration always means an increase in speed, which directly tells you that Kinetic Energy must be increasing.
Calculating Gravitational Potential Energy
Using the GPE formula
Step-by-Step Calculation
- Identify the values: Mass (m) = 2.5 kg, g = 9.8 N/kg, Height (h) = 3.4 m.
- Substitute into the formula: Eₚ = 2.5 × 9.8 × 3.4
- Calculate the final value: 83.3
Correct Answer
83.3 J (or 83 J)
Common Errors
Ensure you use the mass of the block (2.5 kg) as requested, not the mass of the person (which isn't given anyway!).
Calculating Kinetic Energy
Using the KE formula
Step-by-Step Calculation
- Identify the values: Mass (m) = 2.5 kg, Speed (v) = 4.8 m/s.
- Substitute into the formula: Eₖ = 0.5 × 2.5 × 4.8²
- Square the speed first: 4.8 × 4.8 = 23.04
- Complete the sum: 0.5 × 2.5 × 23.04 = 28.8
Correct Answer
28.8 J (or 29 J)
The "Square" Trap
The most common mistake in GCSE Physics is forgetting to square the speed. Always check your calculator work: 0.5 × m × v × v .
Friction and Efficiency
Work done and lubrication
Key Knowledge: Friction
When two surfaces slide past each other (like wheels on a wire), friction acts against the motion. This causes energy to be transferred to the thermal store of the surroundings.
Correct Answers
- 02.5: Some energy is transferred to the surroundings.
- 02.6: The speed will increase because friction is reduced (less work done against friction).
Examiner Insight
For 02.6, you must give two points for 2 marks. Simply saying "he goes faster" only gets 1 mark. You must explain why (less friction/less work done against friction) to get the second mark.
Misconception Alert
Never say energy is "destroyed" or "lost". Energy is always transferred or dissipated. The Law of Conservation of Energy states it cannot be destroyed!
Topics
Physics · P1: Energy
Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 1 (Foundation), 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.