Distance-Time Graphs
Science: KS3, topic 3.2.18
Distance-Time Graphs
We can draw graphs with the axes ‘distance’ and ‘time’ – the gradient will show the speed of an object.
Distance-time graphs
- On a distance-time graph, the x-axis shows the ‘time’, normally in seconds.
- On a distance-time graph, the y-axis shows the ‘distance’, normally in metres.
Line and gradient
- The line on the graph represents the speed.
- The steeper the gradient, the faster the object was going.
- A straight line with a positive gradient (vertical direction) shows an object at a constant speed.
- A curved line with a positive gradient shows an object that is accelerating (speeding up).
- A straight horizontal line shows that an object is stationary (not moving).
Calculating speed
- If an object is travelling at a constant speed, you can use distance ÷ time to calculate its average speed.
- Look at points on the y-axis that the object traveled (the distance) and work out: highest distance – smallest distance.
- Once you have the distance, read the points on the x-axis for the time it took for the object to travel that distance.
- Then use the equation: speed = distance ÷ time.
Test yourself on Distance-Time Graphs
Which of these is true of a distance-time graph?
What does a horizontal straight line on a distance-time graph show about an object?
What is the speed in the middle section of the distance-time graph?
A distance-time graph shows a straight line that becomes less steep after 5 seconds. What does this show about the object's speed after 5 seconds?