Angular Kinetics

This concludes our angular kinetic section. Please re-read the objectives at the beginning of this section and determine if you understand them.  I have compiled a summary review and selected proplems below. 

Selected problems and solutions

CHAPTER OVERVIEW
A body's resistance to linear acceleration (inertia) is proportional to its mass. Resistance to angular acceleration is known as moment of inertia, a quantity that incorporates both the amount of mass and its distribution relative to the axis of rotation. The distribution of mass more critically affects the moment of inertia than does the mass itself.

Just as linear momentum is the product of the linear inertial property (mass) and linear velocity, angular momentum is the product of moment of inertia and angular velocity. In the absence of external torque, angular momentum is conserved. This enables an airborne human performer to alter total body angular velocity by manipulating moment of inertia through changes in body configuration relative to the principal axis around which rotation is occurring. The principle of conservation of angular momentum is based on the angular version of Newton's first law of motion. The second and third laws of motion may also be expressed in angular terms, by simply substituting moment of inertia for mass, torque for force, and angular acceleration for linear acceleration.

In the presence of external torque, angular momentum can be changed. Similar to linear momentum, the changes are dependent on both the amount of torque and the length of time over which it acts. Torque multiplied by time is angular impulse and angular impulse determines the change in angular momentum.