AQA GCSE Physics Physics Paper 2 (Foundation), June 2025: Question 10

7 marks · Standard Demand difficulty · Short Answer

Calculate uncertainty from repeated drop times, identify the type and source of experimental error, and determine the acceleration of a dropped ball from a height against time squared graph.

Practise this question

Question

Question 10 shows a hand holding a 'gravity ball' with a digital stopwatch display and button in Figure 15. The method describes dropping the ball from different heights and recording the time taken to hit the floor. Five recorded times are given: 0.49 s, 0.51 s, 0.58 s, 0.56 s, and 0.61 s. Sub-questions ask to calculate uncertainty, choose whether the error is random, systematic, or zero error, and suggest a reason for it. Figure 16 displays a graph of height dropped in metres against time squared in seconds squared, showing a straight line through the origin up to (0.7, 3.5), followed by a prompt to calculate acceleration using acceleration = 2 × (gradient of the graph).

Mark scheme

Show the mark scheme Mark scheme for Question 10. 10.1: range = 0.61 - 0.49 = 0.12 (1 mark), uncertainty = ± 0.06 s (1 mark). 10.2: random error (1 mark). 10.3: ball dropped from different heights, different initial speeds, or variable delay in starting/stopping (1 mark). 10.4: reading corresponding values from graph such as 3.5 m and 0.70 s² (1 mark), gradient = 5.0 (1 mark), acceleration = 10.0 m/s² (1 mark). Total 7 marks.

How to answer it

Investigating Acceleration Using a Gravity Ball

📋 What this question tests

This question evaluates practical skills in physics: calculating measurement uncertainty from repeat readings, classifying types of experimental error, identifying practical causes of timing variations, and extracting a gradient from a linear graph to determine acceleration due to gravity.

Question 10.1: Calculating Uncertainty

Measurements of time: 0.49 s, 0.51 s, 0.58 s, 0.56 s, 0.61 s [2 marks]

📐 Step-by-Step Calculation

  1. Identify max and min values:
    Maximum = 0.61 s , Minimum = 0.49 s
  2. Calculate range (Mark 1):
    Range = 0.61 − 0.49 = 0.12 s
  3. Calculate uncertainty (Mark 2):
    Uncertainty = Range ÷ 2
    Uncertainty = 0.12 ÷ 2 = ±0.06 s

✅ Mark Scheme Breakdown

  • Mark 1: range = 0.61 − 0.49 or range = 0.12 (also allows mean = 0.55)
  • Mark 2: uncertainty = ± 0.06 (s)
The ± symbol is pre-printed on the answer line, so writing 0.06 secures both marks.

❌ Common Errors

  • Dividing by 5: Students frequently confuse uncertainty with finding the mean and divide the range by the number of readings.
  • Forgetting to halve the range: Writing 0.12 s as the final answer gives only 1 of the 2 marks.

🧠 Exam Technique

Always remember the standard GCSE formula for repeat readings:

Uncertainty = (Maximum Value − Minimum Value) ÷ 2

Question 10.2: Types of Experimental Error

What type of error caused the variation in the measurements of time? [1 mark]

✅ Correct Answer

☑ Random error

💡 Key Knowledge

  • Random errors cause readings to be spread unpredictably about the true value. They are present in all measurements and can be reduced by taking repeats and calculating a mean.
  • Systematic errors cause readings to differ from the true value by a consistent amount each time (e.g., zero errors).

Question 10.3: Causes of Timing Variation

Suggest one reason for the error that caused the variation in time [1 mark]

✅ Acceptable Answers (Any ONE)

  • The ball may have been dropped from slightly different heights each time.
  • The initial speed was not zero (e.g. ball was accidentally pushed/thrown downwards or lifted slightly).
  • There was a variable delay between pressing the start button and releasing the ball.
  • The stopwatch mechanism did not always stop immediately on impact with the floor.

❌ Examiner Pitfall: Vague Answers

  • Never just write "human error" or "reaction time". These are too vague and are routinely awarded 0 marks.
  • Notice the equipment: the ball has a built-in switch that stops automatically on impact, so simple human "stopwatch reaction time on landing" is invalid. You must focus on how the ball was held or released!

Question 10.4: Graph Gradient & Acceleration

Determine the acceleration of the ball using the graph [3 marks]

📐 Step-by-Step Calculation

  1. Step 1: Choose coordinates from the line of best fit (Mark 1)
    Pick points as far apart as possible:
    (0, 0) and (0.70, 3.5)
  2. Step 2: Calculate the gradient (Mark 2)
    Gradient = Change in y ÷ Change in x
    Gradient = 3.5 ÷ 0.70 = 5.0
  3. Step 3: Calculate acceleration using the given equation (Mark 3)
    acceleration = 2 × (gradient)
    acceleration = 2 × 5.0 = 10.0 m/s² (or 10 m/s² )

💡 Physics Behind the Formula

From the equation of motion:

s = ut + ½at²

Because the ball is dropped from rest, initial velocity u = 0 :

s = ½at² ➔ s = (½a) × t²

Comparing to y = mx : the vertical axis y = height (s) , and horizontal axis x = t² . Therefore:

Gradient = ½a ➔ a = 2 × gradient

🧠 Exam Technique: Reading the Graph

  • Always check the axes: x-axis is Time squared (s²), not just time.
  • Draw a clear, large triangle on the graph line to show the examiner where your values came from.
  • Verify your answer makes physical sense: acceleration due to gravity on Earth is approximately 9.8 m/s² , so getting an answer around 10 m/s² confirms you are on track!

❌ Common Errors

  • Stopping at the gradient: Calculating 5.0 and forgetting to multiply by 2 (costs 1 mark).
  • Inverting the gradient: Dividing x by y ( 0.70 ÷ 3.5 = 0.2 ) instead of y by x.

Topics

Physics · P5: Forces

Question and mark scheme from the AQA GCSE Physics examination, Physics Paper 2 (Foundation), June 2025. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.