Physics
Motion
Class 7
Beginner
About 15 min
Premium
Measuring average speed
Time a walker, a runner, a cyclist, a bus and a tortoise over measured distances and calculate their average speeds.
Core concept
Average speed = total distance ÷ total time
Topic: Motion
speed: How far something travels in a certain time, like kilometres per hour. All key words tells us how far something travels in a certain time. To find the average speed, measure the distance travelled with a measuring tape and the time taken with a stopwatch, then divide: average speed = distance ÷ time. Speed is measured in metres per second (m/s) or kilometres per hour (km/h); 1 m/s = 3.6 km/h. For something moving at a steady speed, doubling the distance doubles the time taken.
What you will learn
- Measure distance and time and calculate average speed.
- Show that, at a steady speed, distance travelled is proportional to time.
- Convert speeds between m/s and km/h.
Before you start
- Read a measuring tape and a stopwatch.
Materials
- Chalk to mark the start and finish lines
Equipment
- Measuring tape (100 m)
- Stopwatch
Procedure
- Time the walker over a short, a medium and a long distance and record each run.
- Time the runner and the cyclist and compare their speeds.
- Time the bus and convert its speed into km/h.
How this simulation is simplified
- Each mover keeps a steady speed for the whole run.
- The stopwatch is started and stopped exactly on the lines.