Units of Power
Description
Examples
Power has the dimension length squared mass per time cubed. The SI unit of power is the watt, which is defined as a kilogram meter squared per second cubed.
Maple knows the units of power listed in the following table.
Name
Symbols
Context
Alternate Spellings
Prefixes
watt
W
SI *
watts
SI
poncelet
standard *
poncelets
donkeypower
donkeypowers
horsepower
hp
UK *
horsepowers
boiler
electric
metric
water
ton
refrigeration
tons
abwatt
abW
EMU *
abwatts
statwatt
statW
ESU *
statwatts
planck\{}power
planck *
planck\{}powers
voltampere
VA
power
voltamperes
voltampere\{}reactive
var
voltamperes\{}reactive
An asterisk ( * ) indicates the default context, an at sign (@) indicates an abbreviation, and under the prefixes column, SI indicates that the unit takes all SI prefixes, IEC indicates that the unit takes IEC prefixes, and SI+ and SI- indicate that the unit takes only positive and negative SI prefixes, respectively. Refer to a unit in the Units package by indexing the name or symbol with the context, for example, watt[SI] or abW[EMU]; or, if the context is indicated as the default, by using only the unit name or symbol, for example, watt or abW.
The units of power are defined as follows.
A poncelet is defined as meters kilogramforce per second.
A donkeypower is defined as watts.
A planck power is defined as a planck length squared times planck mass per planck time cubed.
The Horsepower
A horsepower originated as the approximate power with which one horse can pull.
A UK horsepower is defined as feet poundforce per second.
A boiler horsepower is defined as approximately watts.
An electric horsepower is defined as watts.
A metric horsepower, which has been called the cheval vapeur, is defined as the power needed to lift kilograms at meter per second, assuming standard acceleration of free fall.
A water horsepower is defined as approximately watts.
A ton of refrigeration is defined as a short ton International Table British thermal unit per pound day.
The abwatt and statwatt are defined as an erg per second or watt.
See Also
convert/dimensions
convert/units
Units
Units/energy
Units/Index
Units/length
Units/mass
Units/time
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