Unit of Speed

It is important to write the unit of measurement. Speed is the ratio of distance and time. So we use the units of both distance and time to write the unit of speed – kilometer/hour (km/h), kilometer/second (km/s), meter/hour (m/h), meter/minute (m/min), meter/second (m/s) and so on. The division symbol ‘/’ is read or written as ‘per’, as in m/s is read as meters per second.

We choose the unit of speed according to the context. In the case of the scooter rider, we chose km/hour and km/minute to calculate the speed. But if we want to calculate the speed of an ant, then km/hour would be a very large unit. A better choice would be meter/minute. For a snail that moves even slower, cm/second could be a preferred unit for our convenience. 

Note: Once you decide a unit, use the same unit for all measurements for convenience in calculation.