AQA GCSE Combined Science: Trilogy Physics Paper 2 (Foundation), 2023: Question 7

13 marks · Standard Demand difficulty · Extended Answer

Describe a method to investigate the relationship between force and acceleration, identify the relevant Newton's law, and perform calculations using F=ma.

Practise this question

Question

A physics exam question about force and acceleration. Figure 16 shows a trolley on a slightly inclined runway. Question 07.1 asks for a 6-mark method to investigate how force affects acceleration. Table 2 provides a data point: resultant force of 1.2 N gives an acceleration of 1.6 m/s². Subsequent questions ask to identify Newton's law, calculate acceleration for a different force (3.6 N), state the F=ma equation, and calculate mass given a force of 0.42 N and acceleration of 1.2 m/s².
Question text

07 A student investigated how the acceleration of a trolley is affected by the force acting

on the trolley.

Figure 16 shows some of the equipment used.

Figure 16

07.1 Describe a method the student could use.

Your answer should include any extra equipment needed.

[6 marks]

*32* Table 2 shows one set of results for a similar investigation.

Table 2

Resultant force in newtons Acceleration in m/s2

1.2 1.6

07.2 Which of Newton’s laws predicts that the acceleration of the trolley is proportional to

the resultant force on the trolley?

[1 mark]

Tick ( ) one box.

First law

Second law

Third law

07.3 Determine the acceleration of the trolley when the resultant force is 3.6 N.

Use Table 2.

[2 marks]

35 2

Acceleration = m/s

Use the Physics Equations Sheet to answer questions 07.4 and 07.5.

07.4 Write down the equation that links acceleration (a), mass (m) and resultant force (F).

[1 mark]

07.5 A resultant force of 0.42 N acts on a different trolley.

The acceleration of the trolley is 1.2 m/s2.

Calculate the mass of the trolley.

[3 marks]

Mass of trolley = kg

Mark scheme

Show the mark scheme The mark scheme for question 7. For 07.1, it provides a level-based marking grid and indicative content for the experiment, including using pulleys and masses or varying runway height, and measuring time or using light gates. 07.2 identifies Newton's second law. 07.3 shows two methods for calculating acceleration (4.8 m/s²). 07.4 gives the equation F=ma. 07.5 shows the steps to calculate mass as 0.35 kg.

Question 7

AO /

Question Answers Mark

Spec. Ref.

Level 3: The plan would lead to the production of a valid outcome. 5–6

07.1 AO1

All key steps are identified and logically sequenced.

6.5.4.2.2

Level 2: The plan would not necessarily lead to a valid outcome. 3–4

Most steps are identified, but the plan is not fully logically

sequenced.

Level 1: The plan would not lead to a valid outcome. Some 1–2

relevant steps are identified, but links are not made clear.

No relevant content 0

Indicative content

method of varying force

• clamp a pulley onto the edge of the desk

• attach a string to the trolley and place the string over the pulley

• attach a mass holder to the string

or

• vary the height of the runway

• use wooden blocks

measurements

• place a slotted mass on the mass holder

• use W = mg to calculate the force

• mark the starting and finishing points of the trolley on the runway

• measure the distance between the two marks with a metre rule

• time how long it takes to travel between the two marks with a

stopclock / timer

s Δv

• use v = and a =

t t

or

• use light gate(s) to determine time and / or speed

• computer calculates acceleration

• repeat for different numbers of slotted masses

allow a description of a method using–OMBINED SCIENCE: TRIaticker timerLOGY – –

AO /

Question Answers Extra information Mark

Spec. Ref.

07.2 second law 1 AO1

6.5.4.2.2

AO /

Spec. Ref.

07.3 3.6 1 AO3

= 3 6.5.4.2.2

1.2

1.6 × 3 = 4.8 (m/s2) 1

OR

(use of F = ma)

1.2

𝑚 = = 0.75 (1)

1.6

3.6 2

𝑎 = = 4.8 (m/s ) (1)

0.75

AO /

Spec. Ref.

07.4 resultant force = mass × 1 AO1

acceleration 6.5.4.2.2

or

F = ma

AO /

Spec. Ref.

07.5 0.42 = m × 1.2 1 AO2

6.5.4.2.2

0.42 1

m =

1.2

m = 0.35 kg 1

Total Question 7 13

How to answer it

Investigating Force, Mass, and Acceleration

What this question tests

This question assesses your ability to describe the Required Practical for Newton's Second Law, recall the relationship between force and acceleration, and perform calculations using the formula F = m × a .

Part 07.1

Experimental Method (6 Marks)

Describe a method to investigate how force affects acceleration.

💡 Key Knowledge

  • Independent Variable: The force (weight on the string).
  • Dependent Variable: The acceleration of the trolley.
  • Control Variable: The total mass of the system (trolley + all masses).

🧠 Exam Technique

For 6 marks, your method must be logical and sequenced. Use bullet points for clarity. You must explain how you vary the force and how you measure the result.

✅ Model Answer (Level 3: 5-6 Marks)

  1. Setup: Attach a pulley to the end of the runway. Connect the trolley to a mass holder using a string over the pulley.
  2. Friction Compensation: Slightly tilt the runway so the trolley just starts to move (this cancels out friction).
  3. Measurement: Mark two fixed points on the runway a set distance apart. Measure this distance with a metre rule.
  4. Execution: Release the trolley and use a stopwatch to time how long it takes to travel between the marks.
  5. Calculation: Use the time and distance to calculate acceleration (or use light gates connected to a computer for direct acceleration readings).
  6. Varying the Force: Move a mass from the trolley to the mass holder (this increases the pulling force while keeping total mass the same).
  7. Repeat: Repeat the process for at least five different forces and calculate a mean for each.

❌ Common Errors

Students often forget to mention repeating the experiment for different forces. Without this, you haven't "investigated" the relationship, and you cannot score in the top mark band.

Part 07.2 & 07.4

Newton's Second Law

✅ 07.2 Correct Law

Second Law

Newton's Second Law states that acceleration is directly proportional to the resultant force.

✅ 07.4 The Equation

resultant force = mass × acceleration

OR F = m × a

Part 07.3

Using Proportionality

Determine acceleration when force is 3.6 N (using Table 2).

📐 Step-by-Step Calculation

  1. Find the scale factor: The new force (3.6 N) is 3 times larger than the original force (1.2 N).
    3.6 / 1.2 = 3
  2. Apply to acceleration: Because force and acceleration are proportional, multiply the original acceleration by 3.
    1.6 × 3 = 4.8
  3. Final Answer: 4.8 m/s²

🧠 Examiner Tip

You could also calculate the mass first ( m = F / a ), which is 0.75 kg, and then use that to find the new acceleration. Both methods get full marks!

Part 07.5

Calculating Mass

Calculate the mass of a trolley where F = 0.42 N and a = 1.2 m/s².

📐 Step-by-Step Calculation

  1. Substitute values into the formula:
    0.42 = m × 1.2
  2. Rearrange to find m:
    m = 0.42 / 1.2
  3. Calculate final value:
    m = 0.35
  4. Add units: 0.35 kg

1 mark for substitution, 1 mark for rearrangement, 1 mark for correct answer.

❌ Calculation Traps

  • Wrong Rearrangement: Don't do 1.2 / 0.42 . Always put the "Resultant Force" on top when calculating mass or acceleration.
  • Units: Ensure mass is in kg. If the question gave grams, you would need to divide by 1000 first.

Topics

Physics · P5: Forces

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Physics Paper 2 (Foundation), 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.