Why are perpetual motion machines impossible?
In: Physics
Because the whole idea people have when they’re talking about perpetual motion machines is the idea that you can extract energy from a machine without any energy being put in. This is impossible–you can’t create energy from nothing. If you didn’t actually need to extract energy from the thing then you could have a machine that ran for a very long time indeed–use low friction bearings, have the whole thing running in a vacuum so there’s no air resistance, etc–but even then, there will always be *some* losses in the system that will cause the machine to eventually stop.
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