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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
1.4       albertel   33: decibel         dB     # log of pressure amplitude
1.1       www        34: \end{verbatim}
                     35: \subsection*{Prefixes}
                     36: \begin{verbatim}
                     37: #   Prefix     symbol     factor
                     38: 
                     39: yotta            Y         10^{24}
                     40: zetta            Z         10^{21}
                     41: exa              E         10^{18}
                     42: peta             P         10^{15}
                     43: tera             T         10^{12}
                     44: giga             G         10^9
                     45: mega             M         10^6
                     46: kilo             k         10^3
                     47: hecto            h         10^2
1.4       albertel   48: deca             D         10^1
1.1       www        49: 
                     50: deci             d         10^-1
                     51: centi            c         10^-2
                     52: milli            m         10^-3
                     53: micro            u         10^-6
                     54: nano             n         10^-9
                     55: pico             p         10^{-12}
                     56: femto            f         10^{-15}
                     57: atto             a         10^{-18}
                     58: zepto            z         10^{-21}
                     59: yocto            y         10^{-24}
                     60: \end{verbatim}
                     61: \subsection*{Derived Units}
                     62: \begin{verbatim}
                     63: # Derived Unit
                     64: # name       symbol    comment
                     65: 
                     66: gram            g      # mass
1.4       albertel   67: minute          min    # time
1.1       www        68: hour            hr     # time
1.4       albertel   69: hour            h      # time
1.1       www        70: day             day    # time
1.4       albertel   71: day             days   # time
1.1       www        72: year            yr     # time
                     73: pound           lb     # mass
                     74: ounce           oz     # mass
                     75: inch            in     # length
                     76: foot            ft     # length
                     77: mile            mi     # length
                     78: yard            yd     # length
                     79: nautical_mile   n_mi   # length, nautical mile (UK)
                     80: rood            rood   # area, rood
                     81: acre            acre   # area, acre
                     82: hertz           Hz     # frequency
                     83: litre           L      # volume
                     84: newton          N      # force
                     85: pound_force     lbf    # force
                     86: dyne            dyn    # force
                     87: pascal          Pa     # pressure, stress
                     88: bar             bar    # pressure
                     89: mmHg            mmHg   # pressure, millimeter of mercury
                     90: torr            torr   # pressure
                     91: atm             atm    # standard atmosphere
                     92: joule           J      # energy, work, heat
                     93: electronvolt    eV     # energy
                     94: calorie         cal    # energy
                     95: Btu             Btu    # energy
                     96: watt            W      # power, radiant flux
                     97: coulomb         C      # electric charge
                     98: volt            V      # electric potential, electromotive force
                     99: ohm             ohm    # electric resistance, use this in /ANS
                    100: ohm             ohms   # electric resistance
                    101: ohm             Ohm    # electric resistance
                    102: ohm             Ohms   # electric resistance
1.4       albertel  103: mho             mho    # electric conductance
                    104: mho             mhos   # electric conductance
                    105: mho             Mho    # electric conductance
                    106: mho             Mhos   # electric conductance
1.1       www       107: siemens         S      # electric conductance
                    108: farad           F      # electric capacitance
                    109: tesla           T      # magnetic flux density
                    110: weber           Wb     # magnetic flux
                    111: henry           H      # inductance
                    112: radian          rad    # plane angle
                    113: degree          deg    # plane angle (Pi rad=180 deg)
                    114: steradian       sr     # solid angle
                    115: lumen           lm     # luminous flux
                    116: lux             lx     # illuminance
                    117: becquerel       Bq     # activity (radioactive)
1.5       albertel  118: curie           Ci     # activity (radioactive)
1.1       www       119: gray            Gy     # absorbed dose (of radiation)
                    120: sievert         Sv     # dose equivalent (dose equivalent index)
                    121: astroUnit       AU     # mean distance earth to sun
1.2       albertel  122: celcius         degC   # multiplicatively OK
                    123: farenheight     degF   # multiplicatively OK
                    124: molarity        M      # chemisty
                    125: amu             amu    # atomic mass unit
                    126: amu             u      # atomic mass unit
1.6     ! www       127: lightspeed      c      # speed of light
        !           128: cubiccentimeter cc     # cubic centimeter
        !           129: electroncharge  e      # elementary charge
        !           130: hbar            hbar   # Planck constant
        !           131: milesperhour    mph    # miles per hour
        !           132: rpm             rpm    # rounds per minute
        !           133: rpm             rpms   # rounds per minute
        !           134: parsec          pc     # parsec
1.1       www       135: \end{verbatim}
                    136: \subsection*{Interpretation}
                    137: The coded units are interpreted in the order of basic unit, 
                    138: derived unit, then prefix. For example, ``T'' will be matched against 
                    139: ``tesla'' instead of considered the prefix ``T''. Another example is that 
                    140: ``min'' will match
                    141: ``minutes'' instead of treated  as a combination of the prefix ``m'' and units.