Conversion between linear and rotational variables:
Rotational inertia:
Newton’s second law for rotation:
Rotational kinetic energy:
Angular momentum:
Okay, you now have thoroughly studied how an object moves; that is, if the object can be treated as a
point particle. But what happens when an object is spinning? How does that affect motion? Now is the
time to learn.
You’ll find clear similarities between the material in this chapter and what you already know. In fact,
you’ll see that every concept, every variable, every equation for rotational motion has an analog in our
study of translational motion. The best way to understand rotational motion is simply to apply the
concepts of linear motion to the case of a spinning object.
Rotational Kinematics
For an object moving in a straight line, we defined five variables.