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The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10−34 when expressed in the unit J⋅s, which is equal to kg⋅m 2 ⋅s −1, where the metre and the second are defined in terms of c and ΔνCs. — CGPM [7][8]
The International Prototype of the Kilogram (referred to by metrologists as the IPK or Le Grand K; sometimes called the ur -kilogram, [1][2] or urkilogram, [3] particularly by German-language authors writing in English [3][4]: 30 [5]: 64 ) is an object whose mass was used to define the kilogram from 1889, when it replaced the Kilogramme des ...
For example, 1 m/s = 1 m / (1 s) is the coherent derived unit for velocity. [ 1 ] : 139 With the exception of the kilogram (for which the prefix kilo- is required for a coherent unit), when prefixes are used with the coherent SI units, the resulting units are no longer coherent, because the prefix introduces a numerical factor other than one.
The kilogram is the only standard unit to include an SI prefix (kilo-) as part of its name. The gram (10 −3 kg) is an SI derived unit of mass. However, the names of all SI mass units are based on gram , rather than on kilogram ; thus 10 3 kg is a megagram (10 6 g), not a * kilokilogram .
2019 definition: The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10−34 when expressed in the unit J ⋅s, which is equal to kg⋅m 2 ⋅s −1, where the metre and the second are defined in terms of c and ΔνCs.
Imperial units. 0.224809 lbf. The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as , the force which gives a mass of 1 kilogram an acceleration of 1 metre per second squared. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically his second law of motion.
The SI system after the 2019 revision: the kilogram is now fixed in terms of the second, the metre and the Planck constant. The International Committee for Weights and Measures (CIPM) approved a redefinition of the SI base units in November 2018 that defines the kilogram by defining the Planck constant to be exactly 6.626 070 15 × 10−34 kg ...
The sievert (Sv) is equal to one joule per kilogram (1 J⋅kg −1). The katal (kat) is equal to one mole per second (1 mol⋅s −1). Furthermore, there are twenty-four metric prefixes that can be combined with any of these units except one (1) and kilogram (kg) to form further units of the SI. For mass, the same prefixes are applied to the ...