||The English used in this article may not be easy for everybody to understand. (June 2012)|
Speed is the distance that an object moves in a certain amount of time. Speed is a measure of how fast something is moving. The average speed of an object in a certain time is the distance the object traveled divided by the time. Speed is a scalar.
Finding speed [change]
To find speed ,
where is the distance and is the time that has gone by.
Units of measurement for speed [change]
There are many units of measurement for speed. For example, an object's speed can be measured in
- miles per hour (mph),
- kilometers per hour (km/h)
- meters per second (m/s), which is the SI-unit for speed.
Changing speed [change]
When an object changes speed, it gets faster or slower. If the speed of the object increases, it is called acceleration. If the object gets slower, and the speed decreases, it is called deceleration, or negative acceleration.