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A Waving Flag
Anonymous File :-(, x)
Everyone has seen the video of astronauts planting a US flag on the Moon. You can see the flag flexing and rippling. How can that be? There's no breeze on the Moon. But then, there's no atmosphere, either. When the astronauts planted the flagpole they twisted it back and forth to sink it into the lunar soil. On the Earth, that would have made the flag "wave" for a few seconds, then stop. But that's because the flag pushes against air as it flaps, and the air slows it down. On the Moon, there was no air to stop the flag's motion, so it continued, just as Newton's First Law of physics says it should. So of course the cloth flag waved and rippled beneath the metal rod holding it out.
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