I am trying to understand the math for this problem. My instructor did a poor job of explaining it in class. He took a "skyhook" or belt hanger ( looks like a music note make out of wood)" put a stiff belt on it and balanced it on the edge of a table. He exaplained that the center of gravity of the belt (which was at an angle and leaning under the table) was directly under the base of the belt hanger and that made it balance. There has to be a mathematical answer to this. Can someone help?