! Friction, version 1.
! John Wise, initiated 2001/01/12, last updated 2001/01/12.
! Based on "Decay" in "Computational Physics" by N. Giordano.
program Friction
   library "IrGraphics*"
   option nolet
   id$ = "JHW: Friction, nt:100"
   dim t(0), v(0)
   call Init(nt, dt, t0, v0, a)
   mat redim t(0:nt), v(0:nt)
   t(0) = t0
   v(0) = v0
   call Calc(nt, dt, t(), v(), a)
   call Graph1A(id$, "Time", "Velocity", t(), v(), 1)
   print " t = "; t(nt)
   print " v = "; v(nt)
   print "Done"
end
sub Init(nt, dt, t0, v0, a)
   nt = 100          ! number of time steps
   dt = 0.1          ! time step
   t0 = 0            ! initial time
   v0 = 0            ! initial value
   a = 10            ! terminal velocity
end sub
sub Calc(nt, dt, t(), v(), a)
   for i = 1 to nt
      nd = a - v(i-1)
      t(i) = t(i-1) + dt
      v(i) = v(i-1) + nd*dt
   next i
end sub