Comedian Ken Davis tells of the time he gave a speech in his college class. The title of his talk was, “The Law of the Pendulum.” For 20 minutes he carefully explained the principle that governs a swinging pendulum. The law of the pendulum is: A pendulum can never return to a point higher than the point from which it was released. Because of friction and gravity, when the pendulum returns it will fall short of its original release point. Each time it swings it makes less and less of an arc until finally, it is at rest. This point of rest is called the state of equilibrium where all forces acting on the pendulum are equal. As part of his presentation, Davis attached a 3-foot string to a child’s toy top and secured it to the top of the blackboard. He then pulled the top to one side and made a mark on the blackboard where he let it go. Each time it swung back he made a new mark. It took less than a minute for the top to complete its swinging and come to rest. When he finished the d