User:Milton Beychok/Sandbox2: Difference between revisions
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A '''kilogram-force''' ('''kgf''') is a unit of [[force]] equal to the force exerted on one [[kilogram]] of [[mass]] by [[standard gravity]] (''g<sub>n</sub>''), a standardized value representing the average magnitude of [[Acceleration due to gravity|gravitational acceleration]] on [[Earth|Earth's]] surface.<ref name=NIST-gravity/> Therefore, one kilogram-force is by definition equal to 9.80665 [[newton (unit)|newtons]].<ref name=NIST-newton/> | |||
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| | The kilogram-force has never been a part of the [[International System of Units]] (SI), which was introduced in 1960. The SI unit of force is the newton (N). | ||
Prior to this, the unit was widely used in much of the world; it is still in use for some purposes. The thrust of a rocket engine, for example, was measured in kilograms-force in 1940s Germany, in the Soviet Union (where it remained the primary unit for thrust in the Russian space program until at least the late 1980s), and it is still used today in China and sometimes by the European Space Agency. | |||
| | The gram-force and kilogram-force were never well-defined units until the [[CGPM]] adopted a ''standard acceleration of gravity'' of 980.665 cm/s<sup>2</sup> for this purpose in 1901, though they had been used in low-precision measurements of force before that time. | ||
==References== | |||
{{Reflist|refs= | |||
<ref name=NIST-gravity>[http://physics.nist.gov/Pubs/SP330/sp330.pdf The International System of Units (SI), NIST Special Publication 330, 2008 Edition] (pdf page 57 of 77 pdf pages)</ref> | |||
<ref name=NIST-newton>[http://physics.nist.gov/Pubs/SP330/sp330.pdf The International System of Units (SI), NIST Special Publication 330, 2008 Edition] (pdf page 30 of 77 pdf pages)</ref> | |||
}} | |||
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Revision as of 17:47, 2 July 2011
A kilogram-force (kgf) is a unit of force equal to the force exerted on one kilogram of mass by standard gravity (gn), a standardized value representing the average magnitude of gravitational acceleration on Earth's surface.[1] Therefore, one kilogram-force is by definition equal to 9.80665 newtons.[2]
The kilogram-force has never been a part of the International System of Units (SI), which was introduced in 1960. The SI unit of force is the newton (N).
Prior to this, the unit was widely used in much of the world; it is still in use for some purposes. The thrust of a rocket engine, for example, was measured in kilograms-force in 1940s Germany, in the Soviet Union (where it remained the primary unit for thrust in the Russian space program until at least the late 1980s), and it is still used today in China and sometimes by the European Space Agency.
The gram-force and kilogram-force were never well-defined units until the CGPM adopted a standard acceleration of gravity of 980.665 cm/s2 for this purpose in 1901, though they had been used in low-precision measurements of force before that time.
References
- ↑ The International System of Units (SI), NIST Special Publication 330, 2008 Edition (pdf page 57 of 77 pdf pages)
- ↑ The International System of Units (SI), NIST Special Publication 330, 2008 Edition (pdf page 30 of 77 pdf pages)