AQA · GCSE · Physics
Course version: 8463 · Version from Sept 2016
Students should be able to determine speed from a distance–time graph.
Full specification wording
The distance–time relationship: Students should be able to determine speed from a distance–time graph.
Determining a speed from one of these graphs starts with deciding which speed is wanted.
Checked against the AQA 8463 specification (opens in a new tab) on .
- Point 5 of 5
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Determining a speed from one of these graphs starts with deciding which speed is wanted. The speed during one stage comes from the gradient of that stage alone. The average speed for the whole journey comes from the total distance divided by the total time, which is the gradient of a straight line drawn from the first point to the last, and it is smaller than the fastest stage whenever the object stopped on the way. Comparing two objects drawn on the same axes is quicker still, because the steeper line is the faster one and where the lines cross the two objects are at the same distance at the same time. Take the numbers from the axes rather than counting squares, unless the question states what one square represents.
What earns the marks
- Identifying whether a stage speed or an average speed is required.
- The gradient of the chosen section calculated from changes read off the axes.
- Total distance divided by total time where an average is asked for.
- Comparing two lines by their steepness to say which object moves faster.
Common mistakes and how to put them right
Quoting the speed of the steepest stage as the average speed for the journey.
Leaving stationary time out of the total time in an average.
Counting squares without checking what one square represents.
Giving the distance at a stated time as though it were the speed.
Exam tips
- Underline average or during this stage in the question before you start.
- Where two lines cross, the objects are level; it is a common single mark.
Try the lesson
The start of the The distance–time relationship: Students should be able to determine speed from a distance–time graph. lesson, made from checked teaching notes for this specification point.
Have a go first
On a distance–time graph, a straight line rises from 0 m at 0 s to 20 m at 4 s. What is the speed shown by this line?
Listen
Determining a speed from one of these graphs starts with deciding which speed is wanted. The speed during one stage comes from the gradient of that stage alone. The average speed for the whole journey comes from the total distance divided by the total time, which is the gradient of a straight line drawn from the first point to the last, and it is smaller than the fastest stage whenever the object stopped on the way. Comparing two objects drawn on the same axes is quicker still, because the steeper line is the faster one and where the lines cross the two objects are at the same distance at the same time. Take the numbers from the axes rather than counting squares, unless the question states what one square represents. A strong answer earns marks for these points. identifying whether a stage speed or an average speed is required. the gradient of the chosen section calculated from changes read off the axes. total distance divided by total time where an average is asked for. comparing two lines by their steepness to say which object moves faster. Exam tip: Underline average or during this stage in the question before you start.
Key words
Say what each word means before you turn the card.
stage speed
Try answering aloud or in your head before turning the card.
average speed
Try answering aloud or in your head before turning the card.
comparing lines
Try answering aloud or in your head before turning the card.
reading axes
Try answering aloud or in your head before turning the card.
See every definition
- stage speed
- The speed during one stage comes from the gradient of that stage alone.
- average speed
- For the whole journey this comes from the total distance divided by the total time, the gradient of a straight line drawn from the first point to the last.
- comparing lines
- On the same axes the steeper line is the faster one, and where the lines cross the two objects are at the same distance at the same time.
- reading axes
- Take the numbers from the axes rather than counting squares, unless the question states what one square represents.
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of The distance–time relationship: Students should be able to determine speed from a distance–time graph.
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge