Question 5
The table shows the displacement of an object measured at each second as it moved along a straight path.
| Time t (s) | 0 | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| Displacement s (m) | 0 | 4 | 7 | 9 | 12 |
Which statement about this motion is correct?
The right answer is the one marked above.
The velocity is not uniform; the average velocity is 3 m s-1. The displacement grows by 4 m in the first second, 3 m in the second and 2 m in the third, so the velocity is not uniform.
average velocity = 12 m ÷ 4 s = 3 m s-1
That is, the same displacement could have been covered in 4 s at a uniform 3 m s-1. In reality the object moved at different velocities at different moments of the journey.