Newton
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225990425
2008-07-16T10:19:00Z
David Underdown
351737
earliest version of article sued Biriths spellings, so should stay that way per [[WP:ENGVAR]]
{{Otheruses}}
{{Refimprove|date=December 2007}}
The '''newton''' (symbol: '''N''') is the [[International System of Units|SI]] [[SI derived unit|derived unit]] of [[force]], named after [[Isaac Newton]] in recognition of his work on [[classical mechanics]].
==Definition==
The newton is the unit of force derived in the SI system; it is equal to the amount of force required to give a mass of one [[kilogram]] an [[acceleration]] of one [[metre]] per [[second]] squared. Algebraically:
:<math>{\rm 1~N = 1~\frac{kg\cdot m}{s^2}}.</math>
==Examples==
* 1 N is the force of earth's gravity on an object with a mass of about 102 g ({{frac|1|9.8}} kg) (such as a small apple).
* On Earth's surface, a mass of 1 kg exerts a force of approximately 9.81 N [down] (or 1 [[kilogram-force|kgf]]). The approximation of 1 kg corresponding to 10 N is sometimes used as a rule of thumb in everyday life and in engineering.
* The decanewton (daN) = 10 N is increasingly used when specifying load bearing capacity of items such as ropes and anti-vibration mounts, being approximately equivalent to the more familiar non-SI unit of force, the [[kilogram-force|kgf]].
* The force of Earth's gravity on a human being with a mass of 70 kg is approximately 687 N.
* The [[dot product]] of force and distance is [[mechanical work]]. Thus, in SI units, a force of 1 N exerted over a distance of 1 m is 1 N·m of work. The Work-Energy Theorem states that the work done on a body is equal to the change in energy of the body. 1 N·m = 1 J ([[joule]]), the SI unit of energy.
* It is common to see forces expressed in kilonewtons or kN, where 1 kN = 1 000 N.
* A [[tonne]] (metric ton)=(1 000 kg) exerts a force of 9.81 kN (or 1 000 kgf) under [[standard gravity]] conditions on Earth.
==Notes==
{{Units of force}}
{{GravEngAbs}}
==References==
{{reflist}}
* Halliday, Resnick and Walker ''Fundamentals of Physics'', [[John Wiley & Sons]] ISBN 0471470619
==See also==
* [[International System of Units]] (SI)
* The [[joule]], which is the SI unit of [[energy]], equivalent to 1 newton exerted over a distance of 1 metre.
* The [[pascal (unit)|pascal]], the SI unit of [[pressure]], equivalent to 1 newton acting on an area of 1 [[square metre]].
* The [[kilogram-force]], which is the force exerted by Earth's gravity at sea level on one kilogram of mass.
[[Category:Units of force]]
[[af:Newton]]
[[ar:نيوتن (وحدة)]]
[[ast:Newton (unidá)]]
[[bn:নিউটন (একক)]]
[[zh-min-nan:Newton]]
[[be:Ньютан (адзінка вымярэння)]]
[[be-x-old:Ньютан (адзінка вымярэньня)]]
[[bs:Newton (jedinica)]]
[[br:Newton]]
[[bg:Нютон]]
[[ca:Newton (unitat)]]
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[[et:Njuuton]]
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[[zh-classical:牛頓 (單位)]]
[[ko:뉴턴]]
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[[is:Njúton]]
[[it:Newton (unità di misura)]]
[[he:ניוטון (מידה)]]
[[sw:Nyutoni]]
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[[la:Newtonium]]
[[lv:Ņūtons]]
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[[hu:Newton (mértékegység)]]
[[mk:Њутн]]
[[ml:ന്യൂട്ടണ് (അളവ്)]]
[[ms:Newton]]
[[nl:Newton (eenheid)]]
[[new:न्युटन]]
[[ja:ニュートン]]
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[[nn:Eininga newton]]
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[[pl:Niuton]]
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[[ru:Ньютон (единица измерения)]]
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[[sr:Њутн (јединица)]]
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[[uk:Ньютон]]
[[zh-yue:牛頓 (單位)]]
[[zh:牛頓 (單位)]]