V. Oliveira
Abstract This paper presents a simple experiment using the minimum-period condition of a physical pendulum as an alternative to traditional simple pendulum setups used in undergraduate physics laboratories. Rectangular plates were designed and fabricated using 3D printing, with pivot locations positioned at their respective radii of gyration relative to the centre of mass of the plate. Under these conditions, the oscillation period of the plate is mathematically equivalent to that of a simple pendulum with an effective length, ℓ , equal to twice the radius of gyration. The period of oscillation T was experimentally measured using an Arduino micro-controller coupled to a rotary encoder, enabling accurate determination of angular displacement and period. Measurements obtained from plates of different dimensions produced a linear relationship between 4 π 2 ℓ and T 2 , as predicted by theory, with a slope of about 9.80 m s − 2 corresponding to the local acceleration due to gravity. The experiment provides an intuitive framework for exploring rotational dynamics, oscillatory motion, moment of inertia, and the determination of gravitational acceleration in undergraduate laboratory courses.