Unit systems can vary significantly across different scientific and engineering contexts. The atomic system is rooted in fundamental physical constants such as the electron mass and Planck'
The MTS system of units has the meter, tonne, and second as its base units. When used in conjunction with the UseSystem command, the MTS system sets the units for the given dimensions.
Atomic
Example
Electron
Atomic second
Electron mass
Bohr
The atomic system is based on a unit of mass, the electron mass a unit of charge, the electron a unit of action, the planck and a unit of electric permittivity written as kappa0. By taking combinations of these four units, one can derive four units corresponding to the base dimensions length, mass, time, and electric current.
ESU
Abcoulumb
The electrostatic system of units (ESU) has the centimeter, gram, second, and franklin as its base units, where the franklin is energy-equivalent to the unit square root dyne centimeter .For naming consistency, the franklin is called the abcoulomb.
EMU
Abampere
The electromagnetic system of units (EMU) has the centimeter, gram, second, and biot as its base units, where the biot is energy-equivalent to the unit square root dyne (cm−−−√g−√s). For naming consistency, the biot is called the abampere.
CGS
Subtopic
Gram
Centimeter
The CGS system of units has the centimeter, gram, and second as its base units. Although the default CGS system does not include units of electricity or magnetism, the electrostatic and electromagnetic systems, which are also based in the centimeter, gram, and second, do.
MKS
The MKS system of units has the meter, kilogram, and second as its base units. Although the MKS system does not include units of electricity or magnetism, the SI system, which is also based on the meter, kilogram, and second, does.
FPS
Pound
Foot
The FPS system of units has the foot, pound, and second as its base units. Unlike modern systems of units, composite dimensions are not necessarily represented by a product of powers of the base units. For example, the unit of power, the horsepower, is not equal to one square foot pound per cubic second.
SI
Examples
Candela
Mole
Kelvin
Ampere
Second
Kilogram
Meter
Is the International System Units whic most of the countries use to measure distances, weight, time, temperature, etc.
