Kilometre: Difference between revisions

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Template:Unit of length The kilometre (American spelling: kilometer), symbol km^[1] is a unit of length in the metric system, equal to one thousand metres and is therefore exactly equal to the distance travelled by light in free space in 1⁄ 299,792.458 of a second.^[2]

It is the conventionally used measurement unit for expressing distances between geographical places in countries which use the metric system. It is 0.6214 mile.

Slang terms for kilometre include click (sometimes spelled klick or klik) and kay (or k).^[3]^[4] ^[5] ^[6]

Pronunciation

There are two pronunciations for the word:

The former pronunciation follows the general pattern in English whereby metric units of measurement are pronounced with the stress on the first syllable, and preserves the pronunciation of metre. It is generally preferred by the BBC, while most scientists use the pronunciation with stress on the second syllable.^[7]^[8] The latter pronunciation, which follows the stress pattern used for the names of measuring instruments (such as micrometer, barometer, thermometer, tachometer and speedometer), is in common usage as well. Kingsley Amis has suggested that this pronunciation (and the American spelling) be reserved for the thousand-measurer, the wall which Herodotus says Xerxes built around a thousand troops so he could count his army.^[9]

When Australia introduced the metric system, the first pronunciation was declared official by the Metric Conversion Board.

Equivalence to other units of length

1 kilometre	= 1,000 metres
	≈ 0.621 statute miles^[10]
	≈ 1,094 yards^[11]
	≈ 3,281 feet^[12]
	≈ 0.540 nautical miles^[13]
	≈ 6.68×10⁻⁹ astronomical units^[14]
	≈ 1.057×10⁻¹³ light-years^[15]
	≈ 3.24×10⁻¹⁴ parsecs

International usage

The United Kingdom and the United States are the only two developed countries which continue to use miles on road signs.^{[citation needed]}

Although the UK has officially adopted the metric system, there are currently no plans to replace the mile on road signs in the near future, owing to the British public's attachment to traditional imperial units of distance, i.e., miles, yards and inches, and the cost of changing speed signs (which could not be replaced during general maintenance, like distance signs, for safety reasons).^[16]^[17] As of 11 September 2007, the EU has not challenged Britain's use of the imperial system. EU commissioner Günter Verheugen said: "There is not now and never will be any requirement to drop imperial measurements."^[18]

In the US, the National Highway System Designation Act of 1995 prohibits the use of federal-aid highway funds to convert existing signs or purchase new signs with metric units.^[19] However, the Manual on Uniform Traffic Control Devices since 2000 is published in both metric and American Customary Units. (See also Metrication in the United States.)

Notes and references

^ For the purposes of compatibility with Chinese, Japanese and Korean characters there is a Unicode symbol for the kilometre, ㎞, (code 339E).
^ "Brochure, HTML version". Bureau International des Poids et Mesures. Retrieved 2009-06-22.
^ Walshe, Cathy (18 August 2008). "Triathlon: Hewitt bubbling after top 10 finish". The New Zealand Herald. Retrieved 2008-10-27. The race was four laps, and I was just counting down the k's to the end
^ Kuschke, Jazz (21 August 2007). "The great north (off) road". Getaway Magazine via iafrica.com. Retrieved 2008-10-27. yet less than 10 kays down the road
^ "Traveling the Roads to Darwin". Enjoy Darwin. Retrieved 2008-10-27. Camooweal just over the Queensland border a further 250 k's along the road
^ These non-standard terms can also refer to kilometres per hour.
^ http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/tv_and_radio/article3586220.ece.
^ http://www.merriam-webster.com/dictionary/kilometer
^ The King's English: "Kilometre"; Herodotus 7, 60
^ One international statute mile is exactly 1.609344 kilometres.
the rule-of-thumb "multiply by 8 and divide by 5" gives a conversion of 1.6, which is approximately 0.6% too low.
^ One international yard is exactly 0.0009144 kilometres.
^ One international foot is exactly 0.0003048 kilometres.
^ One nautical mile is equal to 1.852 kilometres.
^ One astronomical unit is currently accepted to be equal to 149,597,870,691 ± 30 metres.
^ A light-year is equal to 9,460,730,472,580.8 kilometres, the distance light travels through vacuum in one Julian year of 365.25 days.
^ Andrew Clark (2006-02-23). "Campaign for £80m switch to kilometres". The Guardian. Retrieved 2008-01-07.
^ "Call for metric road sign switch". BBC News Online. BBC. 2006-02-23. Retrieved 2008-01-07.
^ "EU gives up on 'metric Britain'". BBC News Online. BBC. 2007-09-11. Retrieved 2007-10-12.
^ "50th Anniversary of the Interstate Highway System - Frequently Asked Questions". US Department of Transport. Retrieved 2007-10-12.

@@ Line 5: / Line 5: @@
 The '''kilometre''' ([[American English|American spelling]]: '''kilometer'''), symbol '''km'''<ref>For the purposes of compatibility with [[CJK|Chinese, Japanese and Korean characters]] there is a [[Unicode]] symbol for the kilometre, ㎞, (code 339E).</ref> is a [[Units of measurement|unit]] of [[length]] in the [[metric system]], equal to one thousand [[metre]]s and is therefore exactly equal to the distance travelled by [[light]] in [[free space]] in {{frac | [[Speed of light|299,792.458]]}} of a [[second]].<ref>{{cite web|url=http://www.bipm.org/en/si/si_brochure/ | title=Brochure, HTML version | accessdate=2009-06-22 | publisher=Bureau International des Poids et Mesures}}</ref>
-It is the conventionally used measurement unit for expressing distances between geographical places in countries which use the metric system. While it is defined exactly as 1000 m, it equals roughly a ten minutes' walk.
+It is the conventionally used measurement unit for expressing distances between geographical places in countries which use the metric system. It is 0.6214 [[mile]].
 [[Slang]] terms for kilometre include ''click'' (sometimes spelled ''[[klick]]'' or ''klik'') and ''kay'' (or ''k'').<ref>{{cite news|url=http://www.nzherald.co.nz/olympic-games/news/article.cfm?c_id=502&objectid=10527688|quote=The race was four laps, and I was just counting down the k's to the end|title=Triathlon: Hewitt bubbling after top 10 finish|last=Walshe|first=Cathy|date=18 August 2008|publisher=[[The New Zealand Herald]]|accessdate=2008-10-27}}</ref><ref>{{cite news|url=http://motoring.iafrica.com/4x4lifestyle/439909.htm|quote=yet less than 10 kays down the road|title=The great north (off) road|last=Kuschke|first=Jazz|date=21 August 2007|publisher=Getaway Magazine via iafrica.com|accessdate=2008-10-27}}</ref>