- Kilometres per hour
:(For the South African airport with IATA code "KMH", see

Johan Pienaar Airport .)The

**kilometre per hour**(American English :**kilometer per hour**) is a unit of bothspeed (scalar) andvelocity (vector). The unit symbol is**km/h**or**km·h**; however, the colloquial abbreviations "kph" and "kmph" are sometimes also used in English-speaking countries, in analogy to^{−1}mph , although these are not in accordance with international scientific standards. In North Americanslang and military usage, km/h (as well as km) is commonly pronounced, and sometimes even written, as**klicks**or**kays**(K's), although these may also be used to refer tokilometre s.The 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. Along with the kW·h, 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. [*[*]*http://www.bipm.org/en/si/si_brochure/ BIPM brochure*] (SI reference)**Conversions*** 3.6 km/h ≡ 1 m/s, the

SI derived unit of speed,metre per second

* 1 km/h ≈ 0.277 78 m/s

* 1 km/h ≈ 0.621 37 mph ≈ 0.911 34feet per second

* 1 knot ≡ 1.852 km/h (exactly)

* 1 mile = 1.609344 km (~1.61 km) [*1 yard ≡ 0.9144 m and*]

1 mile = 1760 yards thus

1 mile = 1760 × 0.9144 ÷ 1000 km

* 1 mile per hour = ~1.61 kilometres per hour

* 1 kilometre per hour = ~0.62 miles per hour**ee also***

Orders of magnitude (speed) **References****External links*** [

*http://flauna.org/speed/ The converter*] Online conversions for speed units: km/h, mph, knots, etc.

* [*http://www.odometre.com Online Conversions of Metric and Imperial Units*]

* [*http://www.convert-me.com/en/convert/speed Conversion Calculator for Units of Speed*]

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