Graphs can be used as a convenient and precise way of communicating the motion of a body undergoing a complicated series of movements.

Any of the quantities displacement, distance, velocity, speed and acceleration may be plotted as a function of time. Distance and speed are scalar quantities and their values are thus independent of the direction of motion.

Time is said to be the independent variable. Independent variables are normally plotted along the horizontal axis of the graph. The variables which vary as a function of the independent variable, in this case, time, are called dependent variables, and are plotted on along the vertical axis.