Speed

Speed is calculated as:

$v = \frac{d}{t}$

Speed is a scalar quantity (magnitude only, no direction). The SI unit is m/s, but km/h is also commonly used.

Average speed uses total distance divided by total time. Instantaneous speed is the speed at a particular moment.

On a distance-time graph, speed equals the gradient. A steeper line means a faster speed. A curved line means changing speed (acceleration or deceleration).