Center of Mass/Gravity

http://dev.physicslab.org/Document.aspx?doctype=3&filename=RotaryMotion_CenterMass.xml

The attached website beautifully lays out the definitions with pin point examples. In fact many of the examples we have seen in class. Therefore this should not be anything new, rather a reminder. They first begin with defining the center of mass as "the point where all of the mass of the object is concentrated." They then state that when an object is at equilibrium or balanced, then there is not net force. That little piece of info is something from a previous concept that I had forgotten, but was reminded of here. Now towards the bottom of the website, they explain that the pivot point or the axis or rotation must remain above the center of gravity, otherwise the object will no longer be in a state of equilibrium. Overall, a great site with terrific explanations to common examples.