Why would'nt this work?

2 years ago by 𒉀TheGuyTM3𒉁 to c/asklemmy

It can look dumb, but I always had this question as a kid, what physical principles would prevent this?

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tkk13909 238 points 2 years ago

The problem is that when you push an object, the push happens at the speed of sound in that object. It's very fast but not anywhere near the speed of light. If you tapped one end of the stick, you would hear it on the moon after the wave had traveled the distance.

For example, the speed of sound in wood is around 3,300 m/s so 384,400/3,300 ~= 32.36 hours to see the pole move on the moon after you tap it on earth.

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ech 70 points 2 years ago

I swear I've seen a video of someone timing the speed of pushing a very long pole to prove this very thing. If I can find it I'll post it here.

*Found it! https://www.youtube.com/watch?v=DqhXsEgLMJ0 I can't speak to the rigorousness of the experiment, but I remember finding it enlightening.

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nef 9 points 2 years ago

AlphaPhoenix is definitely one of the best scientists on YouTube, that video is good.

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