You Can’t Fool… Gravity (Sep, 1947)

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You Can’t Fool… Gravity

You can trick the human eye, but you can’t fool gravity.

Can a body roll uphill? Yes. But doesn’t that violate the law of gravity? No. How come?

In school we learned that every body has a center of gravity the point at which all the weight of the body can be considered concentrated. Now, can a body roll uphill? Yes. But can the center of gravity roll uphill? No!

Remembering this will help you keep your balance over these two pages.

1 comment
  1. DrewE says: April 27, 20128:30 am

    The airplane one is a bit misleading. A typical airplane with a traditional tail structure, such as here, will have the center of gravity somewhat forward of the center of lift of the wings, and the tail structure provide the necessary downward force to keep things in balance. This is done to ensure stability in flight; with the CG too far aft, things can get rather dicey rather quickly. With broad wings (as shown in the picture), the CG would still be somewhere along the wings, but I’m not so sure that’s necessarily true of airplanes with long, skinny wings like sailplanes; and of course swept or delta wings can move the wingtips well in back of the CG (and the wings center of lift, for that matter).

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