View source for unithelp

{{DavinciWiki_Function|
Displays description of un (unit conversion structure)

This is a user-defined function from constants.dvrc
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Arguments: None; just enter unithelp()

Return Value: Prints description of each element of structure un when not given any input; returns null for any input(s)
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[[Syntax]]: unithelp()
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 dv> un
 struct, 27 elements
     in: 0.0254000
     ft: 0.304800
     mi: 1609.34
     AU: 1.49598e+11
     ly: 9.46073e+15
     pc: 3.08568e+16
     oz: 0.0283495
     lb: 0.453592
     day: 86400.0
     Jyr: 3.15576e+07
     floz: 2.95735e-05
     L: 0.00100000
     gal: 0.00378541
     mph: 0.447040
     ozf: 0.278014
     lbf: 4.44822
     cal: 4.18400
     tTNT: 4.18400e+09
     hp: 746.000
     mbar: 100.000
     torr: 133.322
     psi: 6894.76
     bar: 100000.
     atm: 101325.
     deg: 0.0174533
     arcmin: 0.000290888
     arcsec: 4.84814e-06
 dv> unithelp()
 
 unithelp() describes all unit conversion factors in structure un
 S.Marshall 11-30-2010
 
     Most of these values are from
      http://www.nist.gov/pml/wmd/metric/upload/SP1038.pdf
      via http://www.nist.gov/pml/wmd/metric/metric-pubs.cfm
     Additional sources: http://ssd.jpl.nasa.gov/?constants
      and http://www.iau.org/public/measuring/
 
     Note that definitions vary for mile, pound, ounce, gallon,
      calorie, and horsepower. Those used here are the most common.
 
     The values here are the ratio of the non-SI unit to the
      corresponding SI unit. For instance,
      un.ft &#61; 0.3048 &#61; (one foot)/(one meter), so
      (one foot) &#61; (value of un.ft)*(one meter) &#61; 0.3048 m
 
     in   &#61;     0.0254 m             Inch
     ft   &#61;     0.3048 m             Foot (12 inches)
     mi   &#61;  1609.344 m              Mile (5280 feet)
     AU   &#61;  1.49597870691e+11 m     Astronomical unit
     ly   &#61;  9.4607304725808e+15 m   Light-year (c*Jyr)
     pc   &#61;  3.0856775813e+16 m      Parsec
 
     oz   &#61;  0.028349523125 kg       Ounce mass (avoirdupois, 1/16 lb)
     lb   &#61;  0.45359237 kg           Pound mass (avoirdupois)
 
     day  &#61;  86400 s                 Day (24 hours)
     Jyr  &#61;  3.15576e+07 s           Julian year (365.25 days)
 
     floz &#61;  2.95735295625e-05 m^3   Fluid ounce (1/128 gal)
     L    &#61;  0.001 m^3               Liter
     gal  &#61;  0.003785411784 m^3      US gallon (231 cubic inches)
 
     mph  &#61;  0.44704 m/s             Mile per hour
 
     ozf  &#61;  0.278013850953781 N     Ounce force
     lbf  &#61;  4.4482216152605 N       Pound force
 
     cal  &#61;  4.184 J                 Calorie (thermochemical)
     tTNT &#61;  4.184e+09 J             TNT equivalent tonne
 
     hp   &#61;  746 W                   Horsepower (electric)
 
     mbar &#61;     100 Pa               Millibar
     torr &#61;     133.322368421053 Pa  Torr (1/760 atm)
     psi  &#61;    6894.75729316836 Pa   Pound per square inch
     bar  &#61;  100000 Pa               Bar
     atm  &#61;  101325 Pa               Standard atmosphere
 
     deg    &#61;  0.0174532925199433 rad     Degree (pi/180 radians)
     arcmin &#61;  2.908882086657216e-04 rad  Arcminute (1/60 degree)
     arcsec &#61;  4.848136811095360e-06 rad  Arcsecond (1/60 arcminute)
 
     All except AU and pc are exact (to double precision)
 
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*[[global]]
*[[printf]]
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*[[conhelp]]
*[[solsys]]
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*constants.dvrc
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[[category:Functions]]
[[category:User Defined Functions]]
[[category:General Science]]