Newton
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- This article is about the SI unit of force. For other uses see Newton (disambiguation)
The newton (symbol: N) is the SI unit of force. It is named after Sir Isaac Newton in recognition of his work on classical mechanics.
Contents |
Definition
A newton is the amount of force required to accelerate a mass of one kilogram at a rate of one metre per second squared.
- 1 N = 1 kg·m·s–2
SI multiples
| Multiple | Name | Symbol | Multiple | Name | Symbol | |
|---|---|---|---|---|---|---|
| 100 | newton | N | ||||
| 101 | decanewton | daN | 10–1 | decinewton | dN | |
| 102 | hectonewton | hN | 10–2 | centinewton | cN | |
| 103 | kilonewton | kN | 10–3 | millinewton | mN | |
| 106 | meganewton | MN | 10–6 | micronewton | µN | |
| 109 | giganewton | GN | 10–9 | nanonewton | nN | |
| 1012 | teranewton | TN | 10–12 | piconewton | pN | |
| 1015 | petanewton | PN | 10–15 | femtonewton | fN | |
| 1018 | exanewton | EN | 10–18 | attonewton | aN | |
| 1021 | zettanewton | ZN | 10–21 | zeptonewton | zN | |
| 1024 | yottanewton | YN | 10–24 | yoctonewton | yN |
Explanation
The notions of mass and force are often confused in everyday life, but must be kept separate in science and engineering. The newton was first used around 1904, but not until 1948 was it officially adopted by the General Conference on Weights and Measures (CGPM) as the name for the MKS unit of force. Rather fittingly, given the story about how Newton arrived at his theory of gravity after contemplating why an apple falls downwards, the mass of a small apple exerts a force of about 1 newton on Earth.
Conversions
| Newton (SI unit) | Dyne | Kilopond (kilogram-force) | Pound-force | Poundal | |
|---|---|---|---|---|---|
| 1 N | = 1 kg·m/s² | = 105 dyn | ≈ 0.10197 kp | ≈ 0.22481 lbf | ≈ 7.2330 pdl |
| 1 dyn | = 10−5 N | = 1 g·cm/s² | ≈ 1.0197×10−6 kp | ≈ 2.2481×10−6 lbf | ≈ 7.2330×10−5 pdl |
| 1 kp | = 9.80665 N | = 980665 dyn | = gn·(1 kg) | ≈ 2.2046 lbf | ≈ 70.932 pdl |
| 1 lbf | ≈ 4.448222 N | ≈ 444822 dyn | ≈ 0.45359 kp | = gn·(1 lb) | ≈ 32.174 pdl |
| 1 pdl | ≈ 0.138255 N | ≈ 13825 dyn | ≈ 0.014098 kp | ≈ 0.031081 lbf | = 1 lb·ft/s² |
| The values for the pound-force are calculated using the same value for the standard acceleration of gravity gn which is official for defining the kilopond (a.k.a. kilogram-force), something which is not required. Other values such as gn = 32.16 ft/s² are also used. | |||||
See also
- Isaac Newton
- SI
- dyne, the unit of force of the (mostly obsolete) CGS system, equal to 10 µN.
- kilogram-force
