The inverted pendulum as a probe of anelasticity

We discuss the rich dynamics of an inverted pendulum kept from falling over by an anelastic flexure. The anelastic character of the flexure is dramatically emphasized by the pendulum. We report measurements showing internal friction in one flexure to be independent of frequency over a band of three to four decades. This anelastic behavior in flexures can limit the sensitivity in gravitational wave detectors and in other precision measurements.