Determining the coefficient of kinetic friction using smartphone sensors

Nowadays, smartphones play an important role in the physics laboratory as well as in Arduino-based sensors. Some recent examples include the analysis of acoustic experiments with mobile devices, mechanics experiments such as those on linear and circular motion as well as simple/damped harmonic motion. Smart phones can accurately record experimental data using internal sensors (e.g., accelerometer, gyroscope, magnetometer) via appropriate applications (apps), such as phyphox, SensorLog, and SensorKineticsPro. Moreover, students are familiar with using smartphones and these apps, making these experiments interesting and easy for them to perform. The coefficient of static/kinetic friction can be measured using smartphone sensors, as seen in previous reports. Typically, the coefficient of kinetic friction can be determined by measuring the acceleration of a sliding object (smartphone) on an inclined or horizontal plane. In this paper, we propose alternative methods to measure the coefficient of kinetic friction between a smartphone and paper in linear and circular motions using the smartphone’s sensors. In the experiment, the acceleration of the sliding object (smartphone) is measured using the linear motion method, while its angular speed is measured using the circular motion method. The experimental data are then sent to the user for analysis to determine the coefficient of kinetic friction. The results obtained from the linear motion method are in good agreement with those obtained from the circular motion method.