Dyne

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For other uses, see Dyne (disambiguation).

The dyne (symbol "dyn", from Greek δύναμις (dynamis) meaning power, force) is a unit of force specified in the centimetre–gram–second system of units (CGS), a predecessor of the modern SI. One dyne is equal to 10 µN (micronewtons), or to 10 nsn (nanosthenes) in the old metre–tonne–second system of units. Equivalently, the dyne is defined as "the force required to accelerate a mass of one gram at a rate of one centimetre per second squared":

1 dyn = 1 g⋅cm/s2 = 10−5 kg⋅m/s2 = 10−5 N
1 N = 1 kg⋅m/s2 = 105 g⋅cm/s2 = 105 dyn

The dyne per centimetre is the unit traditionally used to measure surface tension. For example, the surface tension of distilled water is 72 dyn/cm at 25 °C (77 °F);[1] in SI units this is 72×10−3 N/m or 72 mN/m.

Units of force
newton
(SI unit)
dyne kilogram-force,
kilopond
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 value of gn as used in the official definition of the kilogram-force is used here for all gravitational units.

History[edit]

The names dyne and erg were first proposed as units of force and energy in 1861 by Joseph David Everett.[2] The natural units listed in the same text (see Farad in this reference), are those of the metre-gram-second amu.[clarification needed]

The names were reused in 1873 by a Committee of the British Association[3] (of which Everett was reporter) that proposed using the centimetre-gram-second system for electrical and dynamical systems.

References[edit]

  1. ^ [1][dead link]
  2. ^ Rossiter, William (1879). Dictionary of Scientific Terms. London and Glasgow: William Collins, Sons, and Coy. p. 109. 
  3. ^ Thomson, Sir W; Professor GC, Foster; Maxwell, Professor JC; Stoney, Mr GJ; Professor Flemming, Jenkin; Siemens, Dr; Bramwell, Mr FJ (September 1873). Everett, Professor, ed. First Report of the Committee for the Selection and Nomenclature of Dynamical and Electrical Units. Forty-third Meeting of the British Association for the Advancement of Science. Bradford: Johna Murray. p. 223. Retrieved 8 April 2012.