Make up your mind quickly, and then test your decision with a straight edge.
A TERRIBLE TUMBLE
9. From what height must a man fall out of an airship—screaming as he goes overboard—so as to reach the earth before the sound of his cry?
N.B.—Resistance of the air, and the acoustical fact that sound will not travel from a rare to a dense atmosphere, are to be disregarded.
IN A PREDICAMENT
10. Imagine a man on a perfectly smooth table surface of considerable size, in a vacuum, where there is no outside force to move him, and there is no friction. He may raise himself up and down, slide his feet about, double himself up, wave his arms, but his centre of gravity will be always vertically above the same point of the surface.
How could he escape from this predicament, if it was a possible one?