ECZ 2018 · GCE Paper 1 — Travel Graphs
The speed-time graph shows a particle which accelerated uniformly from rest to 20 m/sin 10 seconds, travelled at 20 m/sfor 20 seconds, then decelerated uniformly to rest at t = 55 seconds. What was the speed at 40 seconds?
- A. 8 m/s
- B. 12 m/s
- C. 16 m/s
- D. 10 m/s
Verified working — step 1
Deceleration lasts from 30 s to 55 s (25 s) and takes the speed from 20 m/sto 0. At 40 s, 15 of the 25 seconds remain, so by similar triangles the speed is 20 × 1525= 12 m/s. (Equivalently: deceleration = 2025= 0.8 m/s², and 20 − 0.8 × 10 = …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.
Have a different question?
Search it — if it is from a past paper or a school mock, chances are we have it worked out, or one that uses the same method.
Search any past-paper question