Originally Posted by Phaedrus2129
A meter and a second, etc, are all derived indirectly from the weight of The Kilogram, in France, which is defined as the unit of mass, from which all others are copied and derived.
The speed of light is derived from general relativity. A meter is defined as the distance light travels in some fraction of a second, and a second is derived from quantum energy equations.
There are actually more base units. And I'm quite sure you cannot find seconds and meter only using kg...
( for the exact actual definitions )
And yeah for the French !
There are seven base units of the SI:
The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.
The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 m apart in vacuum, would produce between these conductors a force equal to 2 x 10–7 newton per metre of length.
The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
1.The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.
2.When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.Edited by darknight670 - 7/26/11 at 10:32am