Analysis of the Angular Velocity of a Spinner using Smartphone-Based Measurement

Abstract

Rotation is a fundamental topic in physics education at both secondary and university levels, helping students understand the concepts of torque, moment of inertia, and angular velocity. However, students often encounter difficulties in linking theoretical models with the actual behavior of systems subject to rotational damping. This article presents a study on the decrease in angular velocity of a modified spinner using a smartphone as a measuring device through its gyroscope sensor to explain the mechanism of rotational damping torque and enhance the empirical understanding of the theoretical model. The experimental results show that the angular deceleration exhibits distinct behaviors between the high and low angular velocity ranges. In the high angular velocity range, the decrease follows an exponential relationship, reflecting the influence of linear damping torque caused by air resistance and internal bearing friction. In contrast, in the low angular velocity range, the decrease is nearly linear, consistent with constant frictional torque. The analysis reveals a transition between these two damping mechanisms and suggests that this phenomenon can be effectively used as a case study to help students connect theoretical models with real experimental observations in rotational dynamics.