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1.1       www         1: \label{Physical_Units}
                      2: \section*{Physical Units Accepted by LON-CAPA}
                      3: The following subsections show the physical units that LON-CAPA accepts. 
                      4: The symbols must be used when entering the units, for example {}``35 kg''.
1.3     ! albertel    5: 
        !             6: Note that compound units are formed by using *, / and ^. For example, an acceleration might
        !             7: be in terms of ``m/s^2'' or meters per second squared. This could also be expressed as``m/s/s''.
        !             8: Units of Newton-meters (for torque) would be entered as ``N*m''. Parentheses may be used to guarantee
        !             9: the correct sense of the unit. Kilometers per Ampere-hour could be written as ``km/(A*hr)'' or
        !            10: ``km/A/hr'' but not ``km/A*hr''. The last option would be interpreted as kilometer times hours per Ampere.
        !            11: 
        !            12: LON-CAPA will automatically perform some conversions between units of the same dimension
        !            13: when units are provided for a problem.
        !            14: You can provide an answer of ``1.45 km'' for a distance.
        !            15:  If the computer expects the answer in cm, it will convert your answer before comparing
        !            16: against the numerical solution.
        !            17: 
        !            18: Please note that if your units are inappropriate, the computer has no way of checking
        !            19: the appropriateness of your answer.  If units are required, only once appropriate
        !            20: units are provided will the system check your numerical answer.
        !            21: 
1.1       www        22: \subsection*{Base Units}
                     23: \begin{verbatim}
                     24: # name      symbol     comment
                     25: 
                     26: meter           m      # length
                     27: kilogram        kg     # mass
                     28: second          s      # time
                     29: ampere          A      # electric current
                     30: kelvin          K      # thermodynamic temperature
                     31: mole            mol    # amount of substance
                     32: candela         cd     # luminous intensity
                     33: \end{verbatim}
                     34: \subsection*{Prefixes}
                     35: \begin{verbatim}
                     36: #   Prefix     symbol     factor
                     37: 
                     38: yotta            Y         10^{24}
                     39: zetta            Z         10^{21}
                     40: exa              E         10^{18}
                     41: peta             P         10^{15}
                     42: tera             T         10^{12}
                     43: giga             G         10^9
                     44: mega             M         10^6
                     45: kilo             k         10^3
                     46: hecto            h         10^2
                     47: 
                     48: deci             d         10^-1
                     49: centi            c         10^-2
                     50: milli            m         10^-3
                     51: micro            u         10^-6
                     52: nano             n         10^-9
                     53: pico             p         10^{-12}
                     54: femto            f         10^{-15}
                     55: atto             a         10^{-18}
                     56: zepto            z         10^{-21}
                     57: yocto            y         10^{-24}
                     58: \end{verbatim}
                     59: \subsection*{Derived Units}
                     60: \begin{verbatim}
                     61: # Derived Unit
                     62: # name       symbol    comment
                     63: 
                     64: gram            g      # mass
                     65: hour            hr     # time
                     66: minute          min    # time
                     67: day             day    # time
                     68: year            yr     # time
                     69: pound           lb     # mass
                     70: ounce           oz     # mass
                     71: inch            in     # length
                     72: foot            ft     # length
                     73: mile            mi     # length
                     74: yard            yd     # length
                     75: nautical_mile   n_mi   # length, nautical mile (UK)
                     76: rood            rood   # area, rood
                     77: acre            acre   # area, acre
                     78: hertz           Hz     # frequency
                     79: litre           L      # volume
                     80: newton          N      # force
                     81: pound_force     lbf    # force
                     82: dyne            dyn    # force
                     83: pascal          Pa     # pressure, stress
                     84: bar             bar    # pressure
                     85: mmHg            mmHg   # pressure, millimeter of mercury
                     86: torr            torr   # pressure
                     87: atm             atm    # standard atmosphere
                     88: joule           J      # energy, work, heat
                     89: electronvolt    eV     # energy
                     90: calorie         cal    # energy
                     91: Btu             Btu    # energy
                     92: watt            W      # power, radiant flux
                     93: coulomb         C      # electric charge
                     94: volt            V      # electric potential, electromotive force
                     95: ohm             ohm    # electric resistance, use this in /ANS
                     96: ohm             ohms   # electric resistance
                     97: ohm             Ohm    # electric resistance
                     98: ohm             Ohms   # electric resistance
                     99: siemens         S      # electric conductance
                    100: farad           F      # electric capacitance
                    101: tesla           T      # magnetic flux density
                    102: weber           Wb     # magnetic flux
                    103: henry           H      # inductance
                    104: radian          rad    # plane angle
                    105: degree          deg    # plane angle (Pi rad=180 deg)
                    106: steradian       sr     # solid angle
                    107: lumen           lm     # luminous flux
                    108: lux             lx     # illuminance
                    109: becquerel       Bq     # activity (radioactive)
                    110: gray            Gy     # absorbed dose (of radiation)
                    111: sievert         Sv     # dose equivalent (dose equivalent index)
                    112: astroUnit       AU     # mean distance earth to sun
1.2       albertel  113: celcius         degC   # multiplicatively OK
                    114: farenheight     degF   # multiplicatively OK
                    115: molarity        M      # chemisty
                    116: amu             amu    # atomic mass unit
                    117: amu             u      # atomic mass unit
1.1       www       118: \end{verbatim}
                    119: \subsection*{Interpretation}
                    120: The coded units are interpreted in the order of basic unit, 
                    121: derived unit, then prefix. For example, ``T'' will be matched against 
                    122: ``tesla'' instead of considered the prefix ``T''. Another example is that 
                    123: ``min'' will match
                    124: ``minutes'' instead of treated  as a combination of the prefix ``m'' and units.