Dynamics of a physical pendulum with a magnet in the presence of a coil

Abstract We investigated the dynamics of a wood physical pendulum, supported by a PVC structure and having a magnet glued to its oscillating end and whose oscillation occurred in the vicinity of a coil that was sometimes in short-circuit, sometimes in open-circuit. The pendulum trajectory, position as a function of time, was drawn with the aid of frame-by-frame video analysis, helping to detect a greater damping of the oscillation in the presence of the coil in short-circuit. The equations of motion for the pendulum were modeled and solved, showing to be satisfactory to describe the observed dynamics and, thus, used to make an interesting prediction of interaction between the permanent and induced magnetic fields in the case of an analogous system to be built with distinctive construction characteristics (reduced moment of inertia and increased magnet field). We hope that the work can serve as a stimulus to quantitative investigations of simple systems and will motivate the significant learning of Mechanics and Electromagnetism.