PURPOSE: To show the inverted pendulum dramatically
DESCRIPTION: A rigid rod with a ball on the end is mounted vertically upward from its pivot point, which is the blade mount of a saber saw. If the pivot point is oscillated vertically at a rapid frequency with a small amplitude, the pendulum will have a stable equilibrium position vertically upward, and will slowly execute simple harmonic motion about that position.
SUGGESTIONS: Reducing the voltage to 90 V using a variac results in instability.
REFERENCES: (PIRA 3A60.61) See Demonstration Reference File for a large number of papers discussing the stability and other aspects of the inverted pendulum.
EQUIPMENT: Saber saw inverted pendulum, as photographed.
SETUP TIME: None.
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