Velocity and displacement compared to speed and distance

For the same car journey to pick up your friend from the station and to drive her home, the speed-time graph looks like this.

The graph is similar to the velocity-time graph but the difference is speed is never negative. Speed doesn’t involve direction and so it is always positive.

Let’s look at the velocity-time graph and the speed-time graph side-by-side.

The x-axes are identical in the two graphs. The graph on the left dhows velocity on the y-axis and the graph on the right shows speed on the y-axis. The y-axis on the velocity graph goes from -10 to 10m/s but as speed can’t be negative, the speed graph starts at 0 on the y-axis.

The area under a speed-time graph gives us the distance whereas the area under a velocity-time graph gives us displacement. The distance travelled is 6600m and the displacement is 0m.