Speed: Metres per Second

Lesson 2 of 10 · 7 min · Free, no account needed

What you will learn

Speed = distance ÷ time. Metres divided by seconds gives metres per second, m/s.
Over a whole trip that is the average speed: Bolt's 100 m in 9.58 s is about 10.4 m/s, even though his top speed was higher.
To get km/h, multiply m/s by 3.6: 1 m/s is 3600 m in an hour, which is 3.6 km.

Could Usain Bolt get a speeding ticket in a 30 km/h zone?
Set the needle to your guess for his top speed in the 100 m world record.
Time the 9.58 s world record. Put two gates on the track.
Drag gate A and gate B anywhere, then press Run. Each gate stops a clock as Bolt passes.
Now with a gate every 10 metres. Does he beat 30 km/h?
Each bar is his average speed over that 10 m. The red line is 30 km/h.
That number has a name and a unit.
Speed = distance ÷ time. Metres ÷ seconds gives m/s: metres covered each second.
For the whole race: 100 m ÷ 9.58 s ≈ 10.4 m/s. That is his average speed. His top speed was higher.
m/s × 3.6 = km/h, because 1 m/s is 3600 m in an hour, which is 3.6 km. So 12.4 m/s × 3.6 ≈ 44.7 km/h.
Put each one on its top speed.
The scale grows by ×10 each step, so a snail and a cheetah fit on one line.
Game: catch the bus, four times.
Set your pace so you reach the stop before the bus leaves, without sprinting more than you need.
A speed camera runs on four lines of code. Put them in order.
A car covers 500 m in 20 s. The program should print its speed in km/h.
A cyclist rides 3 km in 10 minutes. What is her speed in m/s?
Turn both into metres and seconds first.
Your four buses. Which one needed the highest speed?
Tap the card. Then check it with speed = distance ÷ time.

Lessons are interactive and need JavaScript. Turn it on to play them.