Graphs of Motion, terms

Learn to read a distance–time graph and a speed–time graph first, since every other idea is really just a way of describing features on one of these two graphs. Gradient comes next, because it is the key that unlocks speed, acceleration and uniform velocity all at once.

The gradient means something different on each graph, and this trips up many students: on a distance–time graph, gradient gives speed, but on a speed–time graph, gradient gives acceleration instead. Average speed is also often confused with uniform velocity, though average speed can hide a lot of speeding up and slowing down.

Questions often ask you to find the gradient of a section of the graph, or to calculate distance travelled as the area under a speed–time graph. Others describe a journey in words and ask you to sketch the matching graph, using terms like uniform velocity or acceleration correctly.