AQA GCSE Physics Physics Paper 1 (Higher), June 2022: Question 9
8 marks · Standard Demand difficulty · Short Answer
Calculate the power output of a girl running up stairs given her mass, height, time, and gravitational field strength, suggest reasons why total power output is greater, and deduce the mass of a boy with different running time and equal power.
Practise this questionQuestion
Question text
09 Figure 10 shows a girl doing an experiment to determine her power output by running
to the top of some stairs.
Figure 10
09.1 The mass of the girl was 60.0 kg.
The height of the stairs was 175 cm.
The girl ran to the top of the stairs in 1.40 s.
gravitational field strength = 9.8 N/kg
Calculate the power output of the girl.
Use the Physics Equations Sheet.
[5 marks]
Power = W
09.2 The total power output of the girl was greater than the answer to question 09.1.
Suggest two reasons why.
[2 marks]
09.3 A boy took more than 1.40 s to run up the same stairs.
The power output of the boy was the same as the power output of the girl.
What conclusion can be made about the boy’s mass?
[1 mark]
Tick ( ) one box.
The boy’s mass was greater than the girl’s mass.
The boy’s mass was lower than the girl’s mass.
The boy’s mass was the same as the girl’s mass.
Mark scheme
Show the mark scheme
AO /
Question Answers Extra information Mark
Spec. Ref.
09.1 h = 1.75 (m) 1 AO2
4.1.1.4
Ep = 60 × 9.8 × 1.75 allow a correct substitution using 1 4.1.1.2
an incorrectly / not converted
value of h
Ep = 1029 (J) allow a correct calculation using 1
an incorrectly / not converted
value of h
1029 allow a correct substitution using 1
P = their calculated value of E
1.40 p
P = 735 (W) allow an answer consistent with 1
their value for Ep
AO /
Spec. Ref.
girl increases her kinetic energy 1
09.2 (as well as increasing her AO2
gravitational potential energy) 4.1.1.1
4.1.2.1
some energy is wasted in her 1
muscles
or
some energy transferred as allow some energy transferred
thermal energy (to due to air resistance
surroundings)
ignore unqualified references to
friction
ignore references to sound
AO /
Spec. Ref.
09.3 the boy’s mass was greater than 1 AO3
the girl’s mass 4.1.1.1
– HYSICS – –
Total Question 9 8
Question 10 21
How to answer it
Determining Power Output
What this question tests
This question assesses your ability to recall and apply energy and power equations, convert units (centimetres to metres), analyze energy transfers in practical situations, and interpret proportional relationships involving mass, time, and power.
Calculating Power Output from Stairs
📐 Step-by-Step Calculation
- Convert height into standard units:
h = 175 cm = 1.75 m (divide by 100). - Calculate Gravitational Potential Energy (Eₚ):
Eₚ = m × g × h
Eₚ = 60.0 × 9.8 × 1.75 = 1029 J - Calculate Power (P):
P = E / t (or Eₚ / t)
P = 1029 / 1.40 = 735 W
❌ Common Errors
- Unit slip: Failing to convert 175 cm into 1.75 m will throw off your entire calculation. Using 175 directly results in 73500 W.
- Equation confusion: Mixing up work done, power, and kinetic energy formulas. Always check the Physics Equations Sheet provided in the exam.
Explaining Discrepancies in Power Output
✅ Correct Answers (Any two)
- The girl also increases her kinetic energy as she speeds up to run up the stairs (not just gravitational potential energy).
- Energy is wasted in her muscles (chemical energy dissipated as thermal energy).
- Energy is transferred as thermal energy to the surroundings due to air resistance.
🧠 Exam Technique & Examiner Guidance
- Be specific: Examiners do not accept vague statements like "friction" without context, as friction isn't the primary resistive force here. Air resistance or thermal energy transfer works best.
- Energy stores: Remember that running involves moving fast, meaning kinetic energy must be accounted for alongside gravitational potential energy.
Comparing Mass and Power
✅ Correct Answer
The boy's mass was greater than the girl's mass. (Tick the first box)
💡 Key Knowledge
- Power = Energy transferred ÷ Time
- If the boy took more time (larger denominator) to climb the exact same height stairs, his energy transferred must have been greater to keep his power output equal to the girl's.
- Since Eₚ = m × g × h, and height and gravity are constant, a larger energy change means the boy's mass ( m ) must be larger.
Topics
Physics · P1: Energy
Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 1 (Higher), June 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.