The speed is \( \frac {20}{10} = 2~m/s\). Key fact The gradient of a distance-time graph represents speed. When displaying a journey, the vertical axis will often represent the distance from a ...

\(gradient = \frac{change~in~y}{change~in~x} = \frac{change~in~distance}{change~in~time} = \frac{change~in~metres}{change~in~seconds} = m/s.\) The gradient of a distance-time graph represents speed.