A student makes the following four statements about physical quantities and their units. For each statement, state whether it is correct or incorrect, giving a reason for each answer. Statement 1: Distance is a vector quantity measured in metres. Statement 2: Velocity is measured in metres per second (m/s) and has both magnitude and direction. Statement 3: Acceleration is a scalar quantity measured in metres per second squared (m/s²). Statement 4: Momentum is measured in kilogram metres per second (kg m/s).
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Statement 1: Incorrect – distance is a scalar quantity; the unit metres is correct.
Statement 2: Correct – velocity is a vector quantity, unit m s⁻¹.
Statement 3: Incorrect – acceleration is a vector quantity; the unit m s⁻² is correct.
Statement 4: Correct – momentum is mass × velocity, unit kg m s⁻¹.
Statement 2: Correct – velocity is a vector quantity, unit m s⁻¹.
Statement 3: Incorrect – acceleration is a vector quantity; the unit m s⁻² is correct.
Statement 4: Correct – momentum is mass × velocity, unit kg m s⁻¹.
Examiner tips
- Use the word ‘Correct’ or ‘Incorrect’ first, then give a brief reason; include the correct SI unit where relevant.
- Remember that distance is scalar, not vector; acceleration is vector, not scalar.
Common mistakes
- Saying distance is a vector; or calling acceleration a scalar.
- Omitting the unit or writing it incorrectly (e.g. m/s² as m/s²²).
Mark scheme (4 marks)
- Statement 1 is incorrect because distance is a scalar quantity (not a vector) — the unit metres is correct but the classification is wrong.
- Statement 2 is correct because velocity is a vector quantity with both magnitude and direction, and its SI unit is m/s.
- Statement 3 is incorrect because acceleration is a vector quantity (not a scalar) — the unit m/s² is correct but the classification is wrong.
- Statement 4 is correct because momentum is the product of mass and velocity and its unit is kg m/s.
Key terms in this question
scalar quantity · vector quantity · velocity · acceleration · momentum
Related
- All Pearson Edexcel International GCSE Physics (4PH1) revision notes →
- How to answer a "State" question →
- Decode the mark scheme abbreviations →
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