This study used a smartphone’s digital compass to observe the rolling motion of a hollow cylinder on
an inclined plane. The smartphone (an iPhone 4s) was attached to the end of one side of a hollow
cylinder to record the experimental data using the SensorLog application. In the experiment, the
change of angular position was measured by the smartphone’s digital compass. The obtained results
were then analyzed and calculated to determine various parameters of the motion, such as the angular
velocity, angular acceleration, critical angle, and coefficient of static friction. The experimental
results obtained from using the digital compass were compared with those obtained from using a
gyroscope sensor. Moreover, the results obtained from both sensors were consistent with the
calculations for the rolling motion. We expect that this experiment will be valuable for use in
physics laboratories.