Rotational Inertia (A+25)

  A+25+0 Two disks, one weighted in center and other on rim, roll down ramp.
  A+25+5 Moment of inertia: Hoop or disk rotated by falling weight.
  A+25+10 Loop the loop: Sphere, hoop, disk rolled down a looped track.
  A+25+15 Rotational Inertia Wands
  A+25+20 Applet: Downhill Racing