#!/usr/bin/ruby

=begin
単位変換をするスクリプト
=end

class Unit
  KT2MS = 1852.0 / 3600.0
  def Unit.kt2ms(kt)
    return KT2MS * kt
  end
  
  MS2KT = 3600.0 / 1852.0
  def Unit.ms2kt(ms)
    return MS2KT * ms
  end
  
  DEG2RAD = Math::PI / 180.0
  def Unit.deg2rad(deg)
    return DEG2RAD * deg 
  end
  
  RAD2DEG = 180.0 / Math::PI
  def Unit.rad2deg(rad)
    return RAD2DEG * rad
  end
  
  G2MS2 = 9.80665
  def Unit.g2ms2(g)
    return G2MS2 * g
  end
  
  MS22G = 1.0 / 9.80665
  def Unit.ms22g(ms2)
    return MS22G * ms2
  end
  
  FT2M = 0.3048
  def Unit.ft2m(ft)
    return FT2M * ft
  end
  
  M2FT = 1.0 / FT2M
  def Unit.m2ft(m)
    return M2FT * m
  end
  
  def Unit.kelvin2rankine(k)
    return k / 5 * 9
  end
  
  def Unit.rankine2kelvin(r)
    return r / 9 * 5
  end
  
  def Unit.celsius2kelvin(c)
    return c + 273.15
  end
  
  def Unit.kelvin2celsius(k)
    return k - 273.15
  end
  
  # 重量(LBM, kg)の変換
  LBM2KG = 0.45359237
  def Unit.lbm2kg(lbm)
    return LBM2KG * lbm
  end
  
  KG2LBM = 1.0 / LBM2KG
  def Unit.kg2lbm(kg)
    return KG2LBM * kg
  end
  
  # 重量ポンド(LBF)とニュートン(N)の変換
  LBF2N = 4.4482216152605
  def Unit.lbf2n(lbf)
    return LBF2N * lbf
  end
  
  N2LBF = 1.0 / LBF2N
  def Unit.n2lbf(n)
    return N2LBF * n
  end
  
  INCH2METER = 0.0254
  def Unit.inch2meter(inch)
    return INCH2METER * inch
  end
  
  def Unit.meter2inch(meter)
    return (1.0 / INCH2METER) * meter
  end
  
  def Unit.slug2kg(slug)
    return LBF2N * slug /  FT2M
  end
  
  # 圧力
  PSI2PA = LBF2N / INCH2METER / INCH2METER #6894.7572931683613367226734453469
  def Unit.psi2pa(psi)
    return PSI2PA * psi
  end
  
  def Unit.pa2psi(pa)
    return (1.0 / PSI2PA) * pa
  end
  
  INHG2PA = 3386.389 # at 0 deg
  def Unit.inHg2pa(inHg)
    return INHG2PA * inHg
  end
  
  def Unit.pa2inHg(pa)
    return (1.0 / INHG2PA) * pa
  end
end