Plotting displacement against time
Graphs that show how an object's displacement varies with time are called displacement–time graphs.
The two axes
These graphs are drawn with displacement on the y axis and time on the x axis.
Time is always on the x axis. That holds for every motion graph, so it is worth learning once.
The data
| Time t (s) | 0 | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|---|
| Displacement s (m) | 0 | 3 | 6 | 9 | 12 | 15 |
The graph
| t (s) | 0 | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|---|
| s (m) | 0 | 3 | 6 | 9 | 12 | 15 |
Marking each pair of values as a point and joining them gives a straight line.
Why a straight line?
Because the displacement increases by the same amount — 3 m — in every second. That is, the velocity is uniform.
You can say that without plotting anything: if the line is straight, the velocity is uniform.