Kilometres per hour

The kilometre per hour (American English: kilometer per hour) is a unit of speed, expressing the number of kilometres travelled in one hour.It has already been stated that, according to Maxwell, when we write down the result of a measurement, the numerical value multiplies the unit. Hence the name of the unit can be replaced by a kind of algebraic symbol, which is shorter and easier to use in formulae. This symbol is not merely an abbreviation but a symbol which, like chemical symbols, must be used in a precise and prescribed manner.100 km/h sign following the most common implementation of the Vienna Convention style (Hungary)Swedish 30 km/h speed limit – the yellow background provides a contrast in case snow covers the background against which one perceives the road sign.Since the text 'km/h' on this Irish speed limit sign is a symbol, not an abbreviation, it represents both 'kilometres per hour' (English) and 'ciliméadar san uair'(Irish)60 km/h speed limit in Arabic and Latin scripts (UAE)Waterways speed limit of 9 km/h (Finland)Samoa uses both miles per hour and kilometres per hour50 km/h sign in Mexico The kilometre per hour (American English: kilometer per hour) is a unit of speed, expressing the number of kilometres travelled in one hour. Internationally, km/h is the most commonly used unit of speed on traffic signs and speedometers. Although the metre was formally defined in 1799, the term 'kilometres per hour' did not come into immediate use – the myriametre (10,000 metres) and myriametre per hour were preferred to kilometres and kilometres per hour. In 1802 the term 'myriamètres par heure' appeared in French literature and many French maps printed in the first half of the nineteenth century had scales in leagues and myriametres, but not in kilometres. The Dutch on the other hand adopted the kilometre in 1817 but gave it the local name of the mijl. Several representations of 'kilometres per hour' have been used since the term was introduced and many are still in use today; for example, dictionaries list 'km/h', 'kmph' and 'km/hr' as English abbreviations. The SI representations, classified as symbols, are 'km/h', 'km h−1' and 'km·h−1'.