Set of three coupled inverted pendulums on wood base.

3A60.50 • B+20+25

diagram for demo

One oscillating mass on rod sets another mass on rod oscillating in resonance. The apparatus consists of two sets of masses on light springy vertical rods. In a set, masses are all the same, but the rods differ in length. The two sets are weakly coupled by a horizontal bar. When mass 1a oscillates, mass 1b starts to oscillate in resonance (but 2a, 2b, 3a & 3b do not oscillate). When mass 2a oscillates, mass 2b oscillates in resonance, etc. Note: Mounting screw must be slightly loose for the demo to work. Mass on light springy rod. Pull and let go.

Related Demos