Fiducia TogetherSpeed, distance and time
The compound measure that appears in every paper and in physics.
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.
What it is
Speed is distance divided by time. Density is mass over volume; pressure is force over area. All three are compound measures using the same triangle.
Where it applies
Both tiers, and physics.
How it works
The commonest source of error is units: mixing minutes with hours, or metres with kilometres, in the same calculation.
Average speed over a journey is total distance over total time, not the mean of the speeds.
How to use it in your work
Convert units first, before substituting.
For average speed, add the distances and add the times. Averaging the speeds is wrong and is a standard trap.
On a distance-time graph, gradient is speed and a horizontal line is stationary.
Where to get help
Your teacher and your board's specification and mark scheme.
Revise this with a song
These are ours. We write revision songs because a lot of people remember a tune when they cannot remember a page, and because revising out loud in the kitchen beats staring at a highlighter.
- The Maths Song The GCSE maths topics, in order.
Where to read more
Last reviewed 2026-08-28 by Fiducia Together · Next review due 2027-08-28
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.