Torsion pendulum revisited

TL;DR

This paper re-examines the dynamics of a torsion pendulum, explaining unexpected behaviors through extended models and providing parameter estimates based on experimental data.

Contribution

It introduces simple extensions to the basic torsion pendulum model to explain observed anomalies and matches these with experimental observations.

Findings

Explanation of torsion mode modulation at higher frequency

Identification of frequency splitting in swinging motion

Estimation of misalignment angles and model parameters

Abstract

We present an analysis of the motion of a simple torsion pendulum and we describe how, with straightforward extensions to the usual basic dynamical model, we succeed in explaining some unexpected features we found in our data, like the modulation of the torsion mode at a higher frequency and the frequency splitting of the swinging motion. Comparison with observed values yields estimates for the misalignment angles and other parameters of the model.