Question 3
The displacement–time graph of an object is shown below.
| t (s) | 0 | 3 | 6 |
|---|---|---|---|
| s (m) | 0 | 12 | 12 |
What can be said about the object's motion between t = 3 s and t = 6 s?
The right answer is the one marked above.
The object is at rest, stopped 12 m from where it started. Over that interval the line runs parallel to the x axis — its gradient is zero.
velocity = (12 − 12) m ÷ (6 − 3) s = 0
The displacement stays at 12 m. Because that displacement is not zero, the object has not come back to its starting point — it has stopped 12 m away from it.