Angular Momentum - 1
For linear motion, we found it very useful to describe motion in terms of the (linear) momentum,
p = m v
Momentum was important because momentum is conserved. That is the total amount of momentum of a system is a constant.
In a similar manner, we will define the angular momentum L of an object as
Angular momentum = (rotational mass) x (angular velocity)
L = I
Like linear momentum, angular momentum is important -- and interesting! -- because angular momentum is conserved! That means the value of the angular momentum remains constant. We can often change the "rotational mass" or the "moment of inertia". This will cause the angular velocity to change to keep the angular momentul L at its original value.
This can give a whole new meaning to the phrase "dizzy Physics professor".
Remember conservation of angular momentum the next time you watch a gymnast, a diver, a ballerina, or an ice skater!
(c) 2005, Doug Davis; all rights reserved
Moment of Inertia Rotational KE Return to ToC, Rotational Kinematics