Analyzing compound pendulum data

Abstract

Abstract The period T of an undamped compound pendulum depends on just three variables, the rotation axis to center of mass distance a, the gyradius k of the pendulum about its center of mass and the gravitational acceleration g. The extraction of these parameters from typical undergraduate measurements of the pendulum period T x as a function of the axis position x is presented. Measurement of just two periods and the pivot displacement Δx allows any two of the parameters to be measured. Three period measurements at pivot displacements b and c allow all three parameters a, k and g to be determined, without any knowledge of the pendulum properties.