Practical skills
Lesson overview
This lesson introduces the core physics idea, the useful equipment and the calculation or data skills used on this page.
What you will learn
Trolley investigation supplied on this page
Use the trolley and hanging mass examples to practise variable control and acceleration calculations.
Force and acceleration practical infographic
Clear explanation
This practical investigates how acceleration changes when resultant force or mass changes. A trolley can be pulled by a hanging mass or driven by another controlled force.
If mass is kept constant, increasing resultant force should increase acceleration. If force is kept constant, increasing mass should reduce acceleration.
Friction, timing resolution and inconsistent release can affect results, so repeat readings and careful setup matter.
Key graph
Key diagram
Worked examples
Using F = m a
A 0.8 kg trolley accelerates at 1.5 m/s2.
F = m a
F = 0.8 x 1.5 = 1.2
Quick checks
Choose an answer, then check your thinking.
1. If mass stays constant, what should happen when resultant force increases?
2. Why are light gates useful in this practical?
Practice questions
Question 1
A 1.2 kg trolley has resultant force 3.6 N. Calculate acceleration.
Reveal answer and marking guidance
Answer: 3 m/s2.
Marking: Credit a = F ÷ m and 3.6 ÷ 1.2 = 3 m/s2.
Question 2
Name one control variable when testing force against acceleration.
Reveal answer and marking guidance
Answer: Mass of the trolley system.
Marking: Credit keeping total mass constant.
Question 3
Why repeat each run?
Reveal answer and marking guidance
Answer: To spot anomalies and calculate a more reliable mean acceleration.
Marking: Credit reliability and anomaly detection.
Question 4
What graph would support F = m a for constant mass?
Reveal answer and marking guidance
Answer: Acceleration against force should be a straight line through the origin.
Marking: Credit direct proportionality between force and acceleration.
Practice ladder
Answers and marking guidance
The exact practice answers are hidden under each question so you can try first. For this lesson, marks come from using the correct physics model, choosing the right equation where needed, keeping units with values, and explaining changes with precise words such as transfer, resultant force, acceleration, evidence and uncertainty.
Common mistakes
- Changing force and mass together without controlling either.
- Ignoring friction on the track.
- Using average speed as acceleration without change in velocity.
- Not resetting the trolley position between runs.
Extension challenge
Design a results table for changing force while keeping total mass constant.
Reveal answer
Example answer: A strong extension response names the physics model, uses accurate units and explains why the evidence supports the conclusion.
Exam-board guidance
Short board notes only. Learn the core physics above first.
AQA GCSE Physics
AQA GCSE Physics: often rewards clear physics explanations, correct equations, units and practical evidence for force, mass and acceleration practical.
OCR GCSE Physics
OCR GCSE Physics: often values precise definitions, clear working, graph interpretation and links between models and evidence.
Pearson Edexcel GCSE Physics
Pearson Edexcel GCSE Physics: often combines the concept with equation use, data handling and practical interpretation.
Eduqas GCSE Physics
Eduqas GCSE Physics: learn the core explanation and practise applying it to unfamiliar contexts, data and practical questions.
WJEC Wales
WJEC Wales: often expects accurate terms, units and evidence-based explanations using the shared physics idea.
CCEA GCSE Physics
CCEA GCSE Physics: connect the idea to your current unit and use the same practical method language your class uses.
Next lesson
Next, continue with Practical: Waves in a Ripple Tank.