A Three Body Problem

Three masses are joined by springs and let loose on a horizontal, frictionless plane. You can reposition the masses by dragging, if you can catch them.

Tags: mechanics, springs, mass, vibration

Inverted Pendulum

An inverted pendulum is in unstable equilibrium..  left to itself, it will topple out of equilibrium. However, if you apply a vibration with a suitably high frequency to the base of the pendulum, you can stabilize it. Try it here.  ω is proportional to the frequency.  A value of 1 does not stabilize the pendulum.  What value does? This is one of the 77 physical paradoxes in Mark Levi’s book Why Cats Land on their Feet.

Tags: pendulum, equilibrium