Speed
Speed is a measure. It is velocity but without the direction.
Finding speed
Speed is the distance an object moves in a given amount of time. The distance is never negative. If a train takes 1 hour to travel 100 kilometers, it has a speed of . In fact this is the average speed. During this one hour, the train may become slower and faster, it may even drive backwards. The average speed of an object in a certain time is the distance the object traveled divided by the time. The instantaneous speed is the average speed when the time is very small, almost zero.
Units
There are many units of measurement. Since the 20th century following units were widely used by humans:
- miles per hour (mph),
- kilometers per hour (km/h), and
- meters per second (m/s), which is the SI-unit for speed.
Different units are used for different applications. People controlling planes and ships frequently use Knot (speed). Sometimes a Mach number is used. The strength of a Wind is its speed, sometimes using the Beaufort scale.
Range
The smallest speed is 0 metres per second. A “negative speed” would be in fact a velocity. The biggest speed is the speed of light. You can write bigger speeds, but they are not possible in this universe.
Read also
- Orbital speed
- Speedometer – a thing showing speed
- Speed limit – a law telling people a maximum speed
- Speed of sound
- Wind speed
Where this page comes from
The article above is adapted from “Speed” on Simple English Wikipedia, by its contributors. We removed reference markers, navigation boxes and tables, expanded measurement templates into readable numbers, and kept the prose otherwise intact.
Both sources are published under CC BY-SA 4.0, so this page is published under the same licence. You may share and adapt it, including commercially, as long as you credit the original and keep the same licence.
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