Speed and velocity is how fast something is moving. It is measured in m/s.

The equation to work out speed is:
Speed = Distance/Time
S = D/T

Acceleration is how fast the velocity/speed is changing. This is measured using:
Acceleration = Change in velocity/Time

On Distance time graphs,
Gradient = Speed.
To work out the gradient, you take the no. on the vertical axis and divide it by the no. on the horizontal line.