# speed

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You can calculate average speed using the equation: speed = distance ÷ time. Average speed cameras are used to find out if a motorist is driving too quickly. A distance-time graph shows how the distance of an object changes over time, and its speed.

# Average speed

The speed of an object tells you how fast or slow it is moving. You can find the average speed of an object if you know:

• The distance travelled
• The time taken to travel that distance

You can calculate average speed using the equation:

Speed = distance ÷ time

Distance-time graphs represent how an object moves. They show how the distance moved from a starting point changes over time.

## Calculating average speed

This equation shows the relationship between average speed, distance and time:

Average speed = distance ÷ time

For example, what is the average speed of a runner who covers 100 m in 10 s?

Average speed = 100 ÷ 10 = 10 m/s

In science, average speed is usually given in metres per second, m/s. If you are given the distance in km, multiply it by 1000 to get the distance in m.

For example, a car covers 2 km in 100 s. What is its average speed?

2 km = 2 × 1000 = 2000 m

Average speed = 2000 ÷ 100 = 20 m/s

Check your understanding of this topic by having a go at this activity:

## Average speed cameras

Speed cameras are used to find out if a motorist is speeding. The camera takes two photographs of the vehicle…