new_contents: #!/usr/bin/env python
  import math
  
  radius = 1.0 # m
  concentric_rings = 3.0 # m
  rps = 2.0 # revs per second
  arm_mass = 4.0 # kg
  
  if __name__ == "__main__":
      diff = radius / (concentric_rings - 1)
      for i in range(0, int(concentric_rings)):
          print "ring %d" % (i,),
          diameter = (diff * i) * 2
          velocity = rps * diameter * math.pi
          print " d=%.2fm v=%.2fms-1 " % (diameter, velocity)
          if diameter > 0:
              print " f=%.2f " % ((arm_mass * velocity * velocity) / (diameter / 2.0), )
  
  
  
subject: add python script for calculating the speed of stuff