Send a car along the road, watch the distance grow and learn how speed, distance and time fit together. Solve missions, win races and beat the clock.
Start here. Speed tells you how far you go in one hour. A cyclist who goes 8 km in every hour has a speed of 8 kilometres per hour, written 8 km/h. After 1 hour you are 8 km away, after 2 hours 16 km, after 3 hours 24 km.
The big rule. Distance = speed × time. For 8 km/h and 3 hours: 8 × 3 = 24 km. The distance–time graph is a straight line, because every hour adds the same distance. The steeper the line, the faster you go.
The D-S-T triangle. Put distance (D) on top and speed (S) and time (T) at the bottom. Cover the one you want to find. Cover D and you see S × T. Cover S and you see D ÷ T. Cover T and you see D ÷ S. For 60 km at 20 km/h: time = 60 ÷ 20 = 3 hours.
Minutes and hours. Speed uses hours, so change minutes into hours first. 30 minutes is half an hour, and 90 minutes is one and a half hours. A car at 40 km/h for 90 minutes goes 40 + 20 = 60 km.
Average speed. Add up all the distance, add up all the time, and divide: average speed = total distance ÷ total time. Do not just average the two speeds.
Meeting and catching up. Two cars driving towards each other close the gap by both speeds added together. A car chasing a cyclist gains the difference of the two speeds every hour.
Other units. Runners are often measured in metres per second. To change km/h into m/s, divide by 18 and multiply by 5. To go the other way, divide by 5 and multiply by 18.
Speed tells you how far something goes in one unit of time, such as one hour or one second. A speed of 50 km/h means 50 kilometres in every hour.
Use the triangle: distance = speed × time, speed = distance ÷ time, and time = distance ÷ speed. Cover the one you want and read what is left.
The slope is the speed. If the line goes up 60 km while going across 2 hours, the speed is 60 ÷ 2 = 30 km/h.
Divide by 60. 30 minutes = 30 ÷ 60 = ½ hour. 45 minutes = ¾ hour. In this game the numbers are chosen so the answers are whole numbers.
Just starting: how far you go in each hour, and counting hours. I know the basics: the D-S-T triangle with hours or seconds. Challenge me: minutes, average speed, graphs, cars that meet or chase, and changing km/h into m/s.
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