Friction (A+12)

  A+12+0 Blocks, with various surfaces slide on an inclined plane.
  A+12+1 Film: "A million to one", flea and dry ice puck, sound, 5 min.
  A+12+5 Weighted wood block dragged horizontally by force sensor.
  A+12+10 Plank oscillates on oppositely rotating bicycle wheels.
  A+12+11 Java Applet "Forces and Motion on Horizontal Plane"
  A+12+12 Java Applet "Forces and Motion on Inclined Ramp"
  A+12+13 Java Applet "Molecular model of Friction"
  A+12+14 Java Applet "Inclined plane with adjustable friction and vectors shown"