Fantastic! Jerry's speed is \(5 \, \mathrm{m/s}\) over the entire 10 seconds of the journey. At some points, Jerry's speed can be more than \(5\), at other times it can be less than \(5\).
When we said that the speed of Jerry was \(5 \, \mathrm{m/s}\), that was the average speed. Just because an object's average speed is \(5 \, \mathrm{m/s}\) doesn't mean that its speed is always \(5 \, \mathrm{m/s}\). So, the speedometer can sometimes show \(2 \, \mathrm{m/s}\), and at other times show \(8 \, \mathrm{m/s}\).

The speedometer measures the speed of an object at that very instant. This speed is called instantaneous speed.