Moment of inertia analysis of rigid bodies using a smartphone magnetometer

Abstract

This study reports the experimental results of the measurement and analysis of the moment of inertia (MOI) of rigid bodies using a smartphone magnetometer. The MOI apparatus comprises a spiral spring, stand, deviation scale, and vibration counter. The magnetometer application used on the smartphone is the Physics Toolbox Sensor Suite. The magnet, which is placed on top of the MOI apparatus, rotates with the rigid body, and the smartphone magnetometer is used to detect the magnetic field values. We experimentally determine the relationship between the magnetic field and time. The time function is used to analyse the oscillation period of the rigid bodies, which comprise a solid cylinder, solid sphere, solid cone, and solid circular disc. The oscillation periods are proportional to the radii of the rigid bodies. This experience will trigger student interest in conducting related experiments.