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Metric and British Units |
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Metric and British Units |
One of the principal advantages of the Metric System is its use of only one unit (standard of size) for each parameter (thing that is being measured). The metric units are interrelated in such a way that only five fundamental standards are necessary. These fundamental standards are identified with an * in the tables below.
| Parameter: | Metric Unit | British Units |
|---|---|---|
| time duration, delay | second * s | second, minute
hour, day |
| frequency | hertz 1/s | cycle per second |
| length distance, displacement | meter 1/299 792 458 light sec m | inch, foot, yard
rod, chain, furlong, mile |
| velocity, speed rate of change of position | meter per second
m/s | foot per second mile per hour, knot |
| acceleration rate of change of velocity | meter per second squared
m/s2 | foot per second squared |
| mass quantity of material | kilogram * kg | ounce, pound, slug, ton |
| force push, pull, or weight | newton kg m/s2 | pound-force |
| impulse force times time | newton second kg m/s | pound-force second |
| momentum mass times velocity | kilogram meter per second
kg m/s | pound foot per second |
| work, energy force times distance | joule (pronounced "jewel")
= one newton meter kg m2/s2 | foot pound-force |
| power rate of doing work | watt = one joule per second kg m2/s3 | foot pound-force per second horsepower |
| area size of a surface | square meter
m2 | square foot, square yard
acre, square mile |
| pressure force per unit area | pascal newton per square meter kg/m s2 | pound-force per square inch |
| volume, capacity | cubic meter (stere) m3 | pint, quart, gallon cubic foot, cubic yard |
| density, heaviness | grams per cubic centimeter
g/cm3 | pounds per cubic foot |
| Parameter: | Metric Heat Unit | British Heat Unit |
|---|---|---|
| heat energy | joule, j calorie, Calorie 1 cal = 4.186 joules 1 Cal = 4186 joules |
British Thermal Unit, BTU |
| temperature change | kelvins, K * | Fahrenheit degree, Fº |
| temperature | kelvins, K | degrees Fahrenheit, ºF |
| Parameter: | Metric Light Unit |
|---|---|
| luminous intensity | candle * |
| luminous flux | lumen one candle produces 4 pi lumens |
| illumination | lux lumen per square meter |
| focus | diopter reciprocal meters |
| astronomical distance | parsec |
| Parameter: | Metric Electrical Unit |
|---|---|
| electric charge | coulomb * 96,500 coul = 1 faraday faraday = 1 mole of electrons |
| electromotive force (EMF) | volt (joule per coulomb) |
| capacitance | farad (coulomb per volt) |
| electric current | ampere (coulomb per second) |
| electric energy | joule (watt second) (newton meter) KWH = 3,600,000 joules |
| electric power | watt (joule per second) |
| electrical resistance | ohm (volt per ampere) |
| electrical conductivity | siemens (coulomb per joule) (ampere per volt) |
| electrical field strength | volts per meter |
| electromagnetic inductance | henry (pl. henrys) |
| magnetic field intensity | oersted (formerly the gauss) |
| magnetic flux | weber (108 maxwells) |
| magnetic flux density | tesla weber per square meter |
| magnetomotive force | gilbert |
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