posted by Carlie on .
Whats the physics behind this?
3 balls are placed at the top of an inclined beam. The beam, attached to a spinning platform, is spun manually. As the platform and beam slows down, the first ball rolls down the beam. The beam instantly speeds up, but slows back down due to friction. This happens 3 times for the 3 balls until there are no more balls and the beam gradually stops spinning.
As the rotating beam slows down due to friction, the centripetal force becomes less and the balls roll down the incline. Each time a ball drops off the low end, the angular velocity increases to keep the angular momentum from changing abruptly.