Abstract: The influence of a frictional torque to the rotation of a rigid disk is analyzed. The equation of the disk＇ s rotation movement are given. Based on these analyses, the experimental research of the disk＇ s rotating is carried out by using video capture and Tracker software. The experimental results confirm the theoretical analyses and give the momentum inertia of the disk in a relatively high precision.

Key words: momentum of the inertia, frictional torque, tracker software, video analysis