ECZ 2016 · GCE Paper 1 — Travel Graphs
The speed-time graph shows a car which accelerates uniformly from rest for 20 seconds to 30 m/s, moves at constant speed until time t, then decelerates and comes to rest at 100 seconds. Given that the total distance travelled is 2 400 metres, calculate the value of t.
- A. 60
- B. 80
- C. 70
- D. 90
Verified working — step 1
Areas: acceleration ½ × 20 × 30 = 300 m; cruise 30(t − 20); deceleration ½ × (100 − t) × 30 = 1500 − 15t. Total: 300 + 30t − 600 + 1500 − 15t = 1200 + 15t = 2400, so 15t = 1200 and t = …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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