Mechanics/Dynamics/Motion

Center of Gravity

 Here's an easy way to find the center of gravity of a long, thin object, even if the object’s weight is unevenly distributed. This exhibit uses a cane or walking stick that is heavier at one end. Supporting the stick by resting each of its ends on a finger, the visitor slowly slides the fingers together until they meet. The fingers will meet under the stick’s center of gravity. The stick’s center of gravity is the place where it can be balanced on just one finger. When the stick is supported with two fingers, in general, one finger (the one that is closer to the center of gravity) will be holding a little more of the weight than the other. As the fingers are drawn closer together, the one that is carrying less weight will slide more easily. This finger will continue to slide more easily until it gets closer to the center of gravity than the other finger, at which point the situation will reverse and the other finger will begin to slide faster. The left and right fingers simply alternate moving until they meet at the center of gravity, where both fingers support equal weight.