A velocity–time graph for a car journey shows three distinct sections: a straight line rising from zero velocity, followed by a horizontal straight line, and finally a straight line falling back to zero velocity. State what each of the three sections tells you about the motion of the car, and state what the area under the entire graph represents.

Cambridge International IGCSE Physics (0625) — 1.2 Motion · State · 4 marks · View as Markdown

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

Model answer (4 marks)

1. The rising straight line shows the car is accelerating at a constant rate.
2. The horizontal straight line shows the car is moving at a constant velocity.
3. The falling straight line shows the car is decelerating at a constant rate (negative acceleration).
4. The area under the entire graph represents the total distance travelled by the car.

Examiner tips

  • Use the exact phrases ‘accelerating at a constant rate’, ‘constant velocity’ and ‘decelerating at a constant rate’ to match the mark scheme.
  • State each point in a separate numbered line to show clear structure.
  • Mention the area as ‘total distance travelled’ – distance, not displacement.
  • Keep the answer concise – no extra words or explanations.

Mark scheme (4 marks)

  1. The rising straight line shows the car is accelerating (at a constant rate / uniformly).
  2. The horizontal straight line shows the car is moving at a constant (steady) velocity / speed.
  3. The falling straight line shows the car is decelerating (at a constant rate / uniformly) / has a negative acceleration.
  4. The area under the entire graph represents the total distance travelled (by the car).

Key terms in this question

velocity–time graph

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