[model]
name-en = "Classic Gravitation"
descrption-en = "Newtonian"
sexprs = ['''
  (=
    F
    (/ (* G m1 m2)
       (square r 2)))
  ''']

[variables]

  [variables.G]
  type = "constant"
  name-en = "Gravitational Constant"
  value_si = 6.674e-11

  [variables.F]
  type = 'dependent'
  name-en = "force"
  units_si = "unit"

  [variables.r]
  type = 'independent'
  name-en = "distance"
  units_si = "meter"

  [variables.m1]
  type = 'independent'
  latex = 'm_1'
  name = "mass #1"
  units_si = "kilogram"

  [variables.m2]
  type = 'independent'
  latex = 'm_2'
  name = "mass #2"
  units_si = "kilogram"

[examples]

  [examples.earth_surface]
  r = 6.371e6       # radius of earth
  m1 = 5.972e24     # mass of earth
  m2 = 70           # mass of human

  [examples.earth_moon]
  r = 385000        # radius of earth
  m1 = 5.972e24     # mass of earth
  m2 = 7.348e22     # mass of moon


[references]
  
  [references.url]
  "Mathworld" = "http://mathworld.wolfram.com/Lotka-VolterraEquations.html"
  "Wikipedia" = "https://en.wikipedia.org/wiki/Lotka%E2%80%93Volterra_equations"