Velocity-time graphs
4 marks · NormalThe table below shows the velocity of a cyclist during a 10-second journey:
| Time / s | Velocity / m/s |
|---|---|
| 0 | 0 |
| 2 | 4 |
| 4 | 8 |
| 6 | 8 |
| 8 | 4 |
| 10 | 0 |
Use the information to answer the following questions.
On graph paper, draw a velocity–time graph for the cyclist's journey. Label your axes.
Describe the motion of the cyclist between 2 s and 6 s.
Describe the motion of the cyclist between 2 s and 6 s.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) — · must show time axis 0–10 s, velocity axis 0–8 m/s, all 6 points plotted correctly, axes labelled with units
(b) The cyclist moves at 8 m/s (constant velocity) from 4 s to 6 s; between 2 s and 4 s, the cyclist accelerates. · must show states constant velocity from 4–6 s, describes acceleration before 4 s
Common mistakes: using time values incorrectly on axes; not labelling axes with units; not recognising constant velocity
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Axes drawn and correctly labelled with units.
A1 (a) · 1 mark · All 6 points plotted accurately.
B1 (b) · 1 mark · States motion is at constant velocity from 4–6 s.
B2 (b) · 1 mark · Describes acceleration before 4 s, or deceleration after 6 s.
Worked solution
a) Plot the points (0,0), (2,4), (4,8), (6,8), (8,4), (10,0) on axes labelled 'Time (s)' and 'Velocity (m/s)'. The graph should increase from 0 to 8 m/s from 0 to 4 s, stay constant from 4 to 6 s, then decrease back to 0 by 10 s.
b) Between 2 and 4 seconds, the cyclist is accelerating (velocity increases from 4 to 8 m/s); from 4 to 6 s, the cyclist moves at constant velocity (8 m/s).