ECZ 2025 · GCE Paper 1 — Travel Graphs
The diagram shows the speed-time graph of an object. The object starts from rest and accelerates uniformly to a speed of 20 m/sin 4 seconds, moves at this constant speed until the 10th second, then decelerates uniformly to rest after a further 5 seconds. Calculate the average speed of the object in the last 4 seconds of the journey.
- A. 16 m/s
- B. 10 m/s
- C. 4 m/s
- D. 8 m/s
Verified working — step 1
The deceleration stage runs from the 10th to the 15th second, losing 20 m/sin 5 s, so the deceleration is 4 m/s². The last 4 seconds run from t = 11 to t = 15. Speed at t = 11 is 20 − 4 × 1 = 16 m/s, and the object stops at t = 15, so the distance is the triangle ½ × 4 × 16 = 32 m. Average speed = 32 ÷ 4 = …The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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