The application of program Tracker at the analyse of rotation motion

A rotation motion of any object in two dimensions can be divided into two parts: the motion of a center of gravity of the object in a space, and rotational motion with respect to the center of gravity of the object. The velocity and direction of motion of an object can be changed by an external force. One possibility of how to see the influence of forces on its motion is to use a dynamic model. The Tracker program was chosen to solve the dynamic model of the rotational motion of the bicycle wheel. Tracker is a free video analysis and modeling tool built on the Open Source Physics (OSP) Java framework. It is designed to be used in physics education. In the dynamic model there are defined force functions and initial conditions for numerical solution of the ordinary differential equations. In the case of rotation or oscillating motion, the expression of the direction and size of the forces are more complicated and in the Help of program there is no information. The paper deals with the expression of a dynamic model for uniform and accelerated rotation motion and wheel rotation around a fixed axis. A fixed axis means that a motion has only one degree of freedom - angle and this effect makes the rotation motion analysis easier.