Graphs can show real situations. On a distance–time graph, the gradient is the speed. A steeper line means faster, and a horizontal line means the object is not moving.
To find a speed, divide the distance travelled by the time taken for that part of the journey. A line going back down towards zero shows the object returning to the start. Read values off the axes carefully, checking the scale on each one.
Worked example
A cyclist travels 12 km in 30 minutes. What is the speed in km per hour?
- 30 minutes is 0.5 hours.
- Speed = 12 ÷ 0.5 = 24.
Answer:24 km/h
Key words
- distance–time graph
- shows how far something has gone over time
- speed
- distance ÷ time
- stationary
- not moving: a flat line
Practise this
New questions every time.
Common Core-referenced: 8.F.B.5