Speed

    AQA
    GCSE

    Speed is defined as the rate of change of distance and is a scalar quantity, distinguished from velocity by the absence of directional components. Candidates must demonstrate proficiency in calculating average speed using the equation v = s/t, rearranging the formula, and performing unit conversions between m/s, km/h, and mph. Analysis of motion requires the interpretation of distance-time graphs, where the gradient represents speed, and the ability to distinguish between uniform and non-uniform motion. Mastery involves applying these concepts to experimental contexts, such as using light gates or ticker timers to measure rapid motion with precision.

    0
    Objectives
    3
    Exam Tips
    4
    Pitfalls
    5
    Key Terms
    4
    Mark Points

    What You Need to Demonstrate

    Key skills and knowledge for this topic

    • Award 1 mark for recalling typical speed values: walking ~1.5 m/s, running ~3 m/s, cycling ~6 m/s.
    • Credit responses that calculate the gradient of a distance-time graph to determine speed.
    • Award marks for correct unit conversions (e.g., minutes to seconds) prior to substitution into v = s/t.
    • Higher Tier: Award method marks for drawing a tangent at a specific time coordinate to determine instantaneous speed.

    Marking Points

    Key points examiners look for in your answers

    • Award 1 mark for recalling typical speed values: walking ~1.5 m/s, running ~3 m/s, cycling ~6 m/s.
    • Credit responses that calculate the gradient of a distance-time graph to determine speed.
    • Award marks for correct unit conversions (e.g., minutes to seconds) prior to substitution into v = s/t.
    • Higher Tier: Award method marks for drawing a tangent at a specific time coordinate to determine instantaneous speed.

    Examiner Tips

    Expert advice for maximising your marks

    • 💡Memorize the specific AQA typical values: walking (1.5 m/s), running (3 m/s), cycling (6 m/s), and sound (330 m/s).
    • 💡When asked to 'Determine' speed from a graph, you must show the gradient calculation on the graph itself (draw the triangle).
    • 💡Check the axis labels carefully; distance is often given in km or cm, requiring conversion to metres for standard SI unit answers.

    Common Mistakes

    Pitfalls to avoid in your exam answers

    • Calculating average speed (total distance / total time) when asked for instantaneous speed on a curved graph.
    • Failing to convert time units to seconds before calculation, leading to order-of-magnitude errors.
    • Confusing the speed of sound in air (330 m/s) with the speed of light or other wave speeds.
    • Drawing small triangles when calculating gradients, which increases the percentage uncertainty of the read values.

    Key Terminology

    Essential terms to know

    Likely Command Words

    How questions on this topic are typically asked

    Calculate
    Determine
    Estimate
    State
    Describe

    Practical Links

    Related required practicals

    • •{"code":"General Practical Skill","title":"Measurement of speed","relevance":"Use of light gates or stopwatches to determine average speed in mechanical contexts"}

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