A student lists four physical quantities and their units. Identify which two quantity–unit pairings are incorrect, and for each incorrect pairing, state the correct SI unit.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
A student writes the following list: • Distance — metre (m) • Weight — kilogram (kg) • Acceleration — metres per second (m/s) • Momentum — kilogram metres per second (kg m/s)
Model answer (4 marks)
Weight – kilogram (kg) – incorrect. The correct SI unit is newton (N).
Acceleration – metres per second (m/s) – incorrect. The correct SI unit is metres per second squared (m/s²).
Acceleration – metres per second (m/s) – incorrect. The correct SI unit is metres per second squared (m/s²).
Examiner tips
- Use the command word ‘identify’ – list the two wrong pairings first, then give the correct units. Show the unit symbols clearly (kg → N, m/s → m/s²).
Common mistakes
- Confusing weight with mass and writing kg for weight. Writing m/s for acceleration instead of m/s².
Mark scheme (4 marks)
- Identifies weight–kilogram as an incorrect pairing
- States the correct SI unit for weight as the newton (N)
- Identifies acceleration–metres per second as an incorrect pairing
- States the correct SI unit for acceleration as metres per second squared (m/s²)
Related
- All Pearson Edexcel International GCSE Physics (4PH1) revision notes →
- How to answer a "Identify" question →
- Decode the mark scheme abbreviations →
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