A kilometer is a unit of length in the metric system. 1 Kilometre
is 1000 metres. Kilometre is abbreviated to km. 8 km is approximately
e.g. say the distance from London to Paris is about 340 km.
The distance round the earth is about 40,000 km.
km / h is the worldwide most commonly used speed unit on road
signs and car speedometers. Therefore, it is far more common
in everyday usage than the proper SI unit of speed, m / s.
km / h is the most commonly used metric unit based on the
hour, which is only a non-SI unit accepted for use with the
International System of Units by the BIPM
Here mentioned example of conversion 3.6 km / h = 1 m / s,
the SI derived unit of speed, metre per second, 1 mile per
hour = 1.61 kilometres per hour (Approx), 1 kilometre per
hour = 0.62 miles per hour (Approx).