Chapter 9 Rotation about a Fixed Axis
We will cover two simple rotations in this chapter.
- Pure Rotation.
- Rolling in a Straight Line.
The rotation of a merry-go-round is an example of a pure rotation and rotation of tires of a car rolling on a straight road is an example of a rolling motion.
In pure rotation, the axis of rotation remains fixed in space. In a rolling motion, the axis moves with the rolling object, but the orientation of the axis does not change. Both of these types of rotation are called fixed-axis rotation. Contrast these to the rotation of a car tire as the car rounds a bend - the direction of axis now changes, hence not a fixed-axis rotation. We will cover non-fixed axis rotation in another chapter.