3 ms·
Even if there is zero surface-surface friction, there is still friction and resistance generated by, eg, the flexing of the materials making contact.
by fiatmoney 11y ago
Even if there is zero surface-surface friction, there is still friction and resistance generated by, eg, the flexing of the materials making contact.
- deleted 11y ago[deleted]
- im3w1l 11y agoGood point, this will bar more complicated mechanisms. But a ring spinning forever around a dimple (in vaccuum of course) should work. Constant pressure so no flexing.
- cbd1984 11y ago"Perfect vacuum" is a classical physics concept which abstracts away quantum effects. In short, it isn't real, and it can never exist. https://en.wikipedia.org/wiki/QED_vacuum https://en.wikipedia.org/wiki/QED_vacuum So, your perpetual motion device will inevitably interact with virtual particles with momentum contrary to its own, and therefore run down. Even if you have problems with that, consider this: It's impossible to cool anything to 0K (absolute zero); all warm bodies (warmer than absolute zero) give off photons; therefore, your moving parts will interact with photons carrying momentum contrary to their own, and therefore be slowed and eventually halted. Again, this is unavoidable. So the simple classical picture of a rock in simple inertial motion through the vacuum of space is valid as a simplification. Remember, though, that it's equally valid to construct a coordinate system where the rock is stationary and everything else is in perpetual motion.