In conclusion, we have constructed an apparatus for the study of the rotational dynamics of a cylindrical plate with the aid of a digital camera and video-analysis freeware, i.e. Tracker . A digital camera plays the role of a data-collecting system and Tracker does the analysis based on the information given in each recorded movie. Three experiments are performed to validate the apparatus and the analytical technique. The first experiment is used to find the coefficient of rotational friction, which can be employed to estimate torque due to rotational friction in the other two experiments. The coefficient turns out to closely approximate that produced by commercial apparatus. Using such a coefficient, we justify that torque due to rotational friction in our experiments can be neglected. The experiments, based on the torque–angular acceleration relation and energy conservation, provide the values of I , which are in agreement with the theoretical value with small variations. It is clear that our demonstration displays the feasibility for practical uses of the apparatus and Tracker in undergraduate laboratories. The complete setup can be simply built from inexpensive materials and Track er is freeware. Despite its low cost, the results the apparatus provides are encouraging and we en vision the possibility of performing similar investigations on other geometries of rigid bodies, such as a spherical object, or a detailed study on frictional force in the system with the same video-analysis technique.