What is Kilometres per hour?
[[File:60 km (ubt).JPG|thumb|Speed limit in km/h on a road in [[Denmark]]]] '''Kilometres per hour''' is a [[unit of measurement]], which measures [[speed]] or [[velocity]]. The unit symbol is '''km/h''' or '''km·h<sup>−1</sup>'''. By [[definition]], an object travelling at a speed of one km/h in a straight line for one [[hour]] moves one [[kilometre]]. The unit is the most commonly used unit of speed worldwide, more common than the [[SI]] unit of speed, [[metre per second|metres per second]]. [[File:WorldMap-speed limit units on traffic signs.png|thumb|upright|[[Speed limit]] units on [[traffic sign]]s around the world: {{legend|#0000FF|Kilometres per hour (km/h)}}{{legend|#FF8000|[[Miles per hour]] (mph)}}{{legend|#22B14C|Both}}{{legend|#ABABAB|No speed limit units}}]] ==Conversions== * 3.6&nbsp;km/h ≡ 1&nbsp;m/s, the [[SI]] unit of speed, [[metre per second]] * 1&nbsp;km/h ≈ 0.277 78&nbsp;m/s * 1&nbsp;km/h ≈ 0.621 37&nbsp;[[miles per hour|mph]] ≈ 0.911 34&nbsp;[[feet per second]] * 1&nbsp;[[knot (speed)|knot]] ≡ 1.852&nbsp;km/h (exactly) * 1 mile = 1.609344 km (~1.61 km) * ''n'' km/h ≈ (1.61 * ''n'') [[mph]] (where ''n'' is a [[quantity]] of speed in km/h) * 1 mph = ~1.6 km/h ==Other websites== *[http://www.convert-me.com/en/convert/speed A conversion calculator for Units of Speed] {{Science-stub}} [[Category:Units of velocity]]