If a stone is dropped from a balloon on a still day, does the stone fall directly below the balloon, or to the west or east of it?

There is no linear motion because it has been established that it is a still day. There is no wind, so the balloon is not moving, and the rock, therefore, is not moving with it. The rock falls straight down.

However, it should land slightly west of the balloon because of the rotation of the earth. Since the sun appears to move from east to west, in actuality the earth is turning from west to east.so in the few seconds of freefall, the earth should turn eastward out from under it, and the rock lands slightly west of the mark.

But this depends on how high the balloon is in the atmosphere. Only at a very high altitude where the air is very thin will this apply. Otherwise, because the balloon and rock are in thick air, they are moving with the atmosphere , so will have enough linear motion to compensate for the rotation of the earth. In other words, the atmosphere has the same motion as the earth, therefore no linear motion across the surface of the earth.

Posted by Bret on 2005-07-08 00:33:37