Distance and displacement

    AQA
    GCSE

    Distance is defined as a scalar quantity representing the total path length covered by an object during motion, regardless of direction. In contrast, displacement is a vector quantity measuring the straight-line distance and specific direction from the starting point to the finishing point. Candidates must distinguish between these quantities to analyze motion accurately, particularly when calculating speed versus velocity. Mastery involves resolving vectors in one dimension and, for higher tiers, utilizing trigonometry or scale drawings for two-dimensional motion.

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    Objectives
    3
    Exam Tips
    3
    Pitfalls
    4
    Key Terms
    4
    Mark Points

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Award 1 mark for stating that distance is a scalar quantity and displacement is a vector quantity
    • Credit responses that define displacement as the distance in a straight line from start to finish, including a specific direction
    • Award 1 mark for drawing vector arrows to scale, connected head-to-tail, with the resultant drawn from the start of the first to the end of the last
    • Award 1 mark for calculating the resultant magnitude using Pythagoras' theorem (Higher Tier only)

    Marking Points

    Key points examiners look for in your answers

    • Award 1 mark for stating that distance is a scalar quantity and displacement is a vector quantity
    • Credit responses that define displacement as the distance in a straight line from start to finish, including a specific direction
    • Award 1 mark for drawing vector arrows to scale, connected head-to-tail, with the resultant drawn from the start of the first to the end of the last
    • Award 1 mark for calculating the resultant magnitude using Pythagoras' theorem (Higher Tier only)

    Examiner Tips

    Expert advice for maximising your marks

    • 💡Always underline the word 'displacement' in the question stem as a prompt to include a direction in your final answer
    • 💡When drawing scale diagrams, choose a scale that allows the diagram to fill at least half the provided space to minimize percentage error
    • 💡For Higher Tier, if vectors are at right angles, use Pythagoras to check the accuracy of your scale drawing

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Providing a displacement answer as a magnitude only (e.g., '50m') without specifying the direction (e.g., 'North' or a bearing)
    • Adding perpendicular vectors algebraically (e.g., 3m + 4m = 7m) rather than geometrically to find the resultant
    • Drawing scale diagrams with thick, blunt pencils, leading to precision errors outside the allowed tolerance

    Key Terminology

    Essential terms to know

    Likely Command Words

    How questions on this topic are typically asked

    State
    Describe
    Calculate
    Draw
    Determine

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