A cyclist rides along a straight road. For the first part of the journey, the cyclist accelerates from rest to a steady speed. The cyclist then maintains this steady speed before slowing to a stop at a set of traffic lights. Describe what a velocity-time graph of this entire journey would look like, and state what feature of the graph could be used to find the total distance travelled.

Pearson Edexcel International GCSE Physics (4PH1) — 1.2 Movement and position · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

The graph consists of three straight‑line sections.
1. From the origin a straight line with a positive slope – this shows the cyclist accelerating from rest.
2. A horizontal straight line – this represents the constant speed phase.
3. A straight line with a negative slope returning to the time axis – this shows the cyclist decelerating to a stop.
The total distance travelled can be found from the area under the velocity‑time curve (the area between the line and the time axis).

Examiner tips

  • Use the command word ‘describe’ – give the shape of each section and the sign of the gradient. Mention the area under the curve as the distance. Keep the answer concise and use the exact terms ‘slope’, ‘horizontal’, ‘area under the curve’.
  • Include the word ‘steady’ or ‘constant’ for the middle section to show you recognise the zero gradient.

Mark scheme (4 marks)

  1. The first section of the graph is a straight line with a positive gradient (sloping upward from zero), showing the cyclist accelerating from rest.
  2. The second section is a horizontal straight line (zero gradient), showing the cyclist travelling at constant/steady speed.
  3. The final section is a straight line with a negative gradient (sloping downward) back to zero velocity, showing the cyclist decelerating to a stop.
  4. The total distance travelled is found from the area under the line / area between the line and the time axis.

Key terms in this question

velocity-time graph · distance

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