Experimental analysis of a compound pendulum with variable suspension point

Abstract

A compound pendulum with variable point of suspension—and hence variable moment of inertia—is experimentally analysed. In particular, the period of the small oscillations as a function of position of the suspension point is measured using three different methods: a smartphone used both as an independent tool or as a data-logger and commercial photo-gate. The experimental results are successfully compared with two theoretical calculations—one of them taking all the dimensions into account and the other using a simplified geometry—based on the addition of moments of inertia and the parallel axis theorem.