Return to Physical_Units.tex CVS log

Up to [LON-CAPA] / loncom / html / adm / help / tex

- BUG#4722

    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''.
    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: 
   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
  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
  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.