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LaTeX syntax
\label{Physical_Units}
\section*{Physical Units Accepted by LON-CAPA}
The following subsections show the physical units that LON-CAPA accepts.
The symbols must be used when entering the units, for example {}``35 kg''.
Note that compound units are formed by using *, / and \^{}. For example, an acceleration might
be in terms of ``m/s\^{}2'' or meters per second squared. This could also be expressed as``m/s/s''.
Units of Newton-meters (for torque) would be entered as ``N*m''. Parentheses may be used to guarantee
the correct sense of the unit. Kilometers per Ampere-hour could be written as ``km/(A*hr)'' or
``km/A/hr'' but not ``km/A*hr''. The last option would be interpreted as kilometer times hours per Ampere.
LON-CAPA will automatically perform some conversions between units of the same dimension
when units are provided for a problem.
You can provide an answer of ``1.45 km'' for a distance.
If the computer expects the answer in cm, it will convert your answer before comparing
against the numerical solution.
Please note that if your units are inappropriate, the computer has no way of checking
the appropriateness of your answer. If units are required, only once appropriate
units are provided will the system check your numerical answer.
\subsection*{Base Units}
\begin{verbatim}
# name symbol comment
meter m # length
kilogram kg # mass
second s # time
ampere A # electric current
kelvin K # thermodynamic temperature
mole mol # amount of substance
candela cd # luminous intensity
decibel dB # log of pressure amplitude
\end{verbatim}
\subsection*{Prefixes}
\begin{verbatim}
# Prefix symbol factor
yotta Y 10^{24}
zetta Z 10^{21}
exa E 10^{18}
peta P 10^{15}
tera T 10^{12}
giga G 10^9
mega M 10^6
kilo k 10^3
hecto h 10^2
deca D 10^1
deci d 10^-1
centi c 10^-2
milli m 10^-3
micro u 10^-6
nano n 10^-9
pico p 10^{-12}
femto f 10^{-15}
atto a 10^{-18}
zepto z 10^{-21}
yocto y 10^{-24}
\end{verbatim}
\subsection*{Derived Units}
\begin{verbatim}
# Derived Unit
# name symbol comment
gram g # mass
minute min # time
hour hr # time
hour h # time
day day # time
day days # time
year yr # time
pound lb # mass
ounce oz # mass
inch in # length
foot ft # length
mile mi # length
yard yd # length
nautical_mile n_mi # length, nautical mile (UK)
rood rood # area, rood
acre acre # area, acre
hertz Hz # frequency
litre L # volume
newton N # force
pound_force lbf # force
dyne dyn # force
pascal Pa # pressure, stress
bar bar # pressure
mmHg mmHg # pressure, millimeter of mercury
torr torr # pressure
atm atm # standard atmosphere
joule J # energy, work, heat
electronvolt eV # energy
calorie cal # energy
Btu Btu # energy
watt W # power, radiant flux
coulomb C # electric charge
volt V # electric potential, electromotive force
ohm ohm # electric resistance, use this in /ANS
ohm ohms # electric resistance
ohm Ohm # electric resistance
ohm Ohms # electric resistance
mho mho # electric conductance
mho mhos # electric conductance
mho Mho # electric conductance
mho Mhos # electric conductance
siemens S # electric conductance
farad F # electric capacitance
tesla T # magnetic flux density
weber Wb # magnetic flux
henry H # inductance
radian rad # plane angle
degree deg # plane angle (Pi rad=180 deg)
steradian sr # solid angle
lumen lm # luminous flux
lux lx # illuminance
becquerel Bq # activity (radioactive)
curie Ci # activity (radioactive)
gray Gy # absorbed dose (of radiation)
sievert Sv # dose equivalent (dose equivalent index)
astroUnit AU # mean distance earth to sun
celcius degC # multiplicatively OK
fahrenheit degF # multiplicatively OK
molarity M # chemisty
amu amu # atomic mass unit
amu u # atomic mass unit
lightspeed c # speed of light
cubiccentimeter cc # cubic centimeter
electroncharge e # elementary charge
hbar hbar # Planck constant
milesperhour mph # miles per hour
rpm rpm # rounds per minute
rpm rpms # rounds per minute
parsec pc # parsec
\end{verbatim}
\subsection*{Interpretation}
The coded units are interpreted in the order of basic unit,
derived unit, then prefix. For example, ``T'' will be matched against
``tesla'' instead of considered the prefix ``T''. Another example is that
``min'' will match
``minutes'' instead of treated as a combination of the prefix ``m'' and units.
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