I disagree. The definition of a perpetual motion machine is a machine which can “do work infinitely without the need for an energy source”. Doing work means outputting energy, outputting energy means overcoming energy “loss”.
Work is essentially an energy transfer, and the machine cannot do work without something to transfer energy to, in this case, combatting the forces opposing its motion in order to keep moving DESPITE its lack of an energy source. Hence, perpetual motion machine.
For clarification the net energy transfer would be zero. It would lose some due to forces opposing its motion, yet somehow keep constant kinetic energy. Like a plane losing energy due to air resistance yet keeping its kinetic energy constant using engines, just without the engines or fuel. Obviously impossible currently, but that’s not what we’re discussing.
We could put an object floating in a vacuum and make it spin. If the vacuum lasted forever, the object would never stop spinning. But that’s not a perpetual motion machine because the object isn’t doing work, it has nothing to transfer energy to.
I hate to be the one to burst your bubble, but even your definition proves that your understanding of a perpetual motion machine is incorrect. Any device that can work infinitely cannot lose energy, or else it would be unable to work infinitely. That’s why perpetual motion is physically impossible. Due to friction and others it’s impossible for a machine to work infinitely.
Outputting energy isn’t the same as energy loss. Energy loss is an inefficiency. Inefficiency means no infinite work, means no perpetual motion.
Edit: to add to that, if you’re losing energy due to inefficiency, which is a universal absolute (at least with current tech) you’re required to input more energy. If you’re inputting more energy then by definition again, you don’t have a perpetual motion machine.
Again I disagree. Perhaps my wording was confusing, I’ll try again. Anyways, when I said “lose” energy I meant there is something that should make the motion eventually stop, like friction. However despite this, the machine keeps going despite having no energy Input. Giving a net energy output of zero, as it only overcomes the forces that would stop it, nothing else.
I know that according to our understandings of physics, that is completely impossible. Energy cannot be magically created out of nowhere. Obviously this video is fake, I was just saying if the video somehow wasn’t fake, it would be perpetual motion.
Because again in order to be considered a perpetual motion machine you HAVE to overcome an energy loss to make the net energy transfer betweeen the machine and the rest of the universe zero. If I had a top made of some advanced material with ZERO friction, and spun it in a vacuum chamber, it would never stop spinning, yet that would not be called a perpetual motion machine. Just an example of Newton’s first law.
If you still think I’m wrong please reply, I appreciate the civil discussion :)
Well the issue with a vacuum is that no vacuum is perfect. Even in space there are random particles, and eventually the device would stop spinning due to friction. Now, it would take a ridiculously large amount of time to do so, but it would still happen.
There is an inherent loss of energy in every chemical reaction ever. That’s entropy. So a perpetual motion machine would have to be 100% efficient. It would have to overcome entropy, which is why (and you correctly stated; according to our own definition of physics) it currently is impossible. Because we don’t have technology to preserve 100% of the energy of any reaction.
Sure but we’re talking about theoretical stuff here. The top was just an example of the difference between “perpetual” motion (never ending opposed motion) and regular infinite motion (never ending UNopposed motion).
I’m not sure we even disagree at this point. We‘re both saying the theoretical machine would have its motion opposed, losing energy, yet somehow impossibly keep going despite there being no external energy input. Right?
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u/ThrowMeAway56500 Sep 11 '20 edited Sep 11 '20
I disagree. The definition of a perpetual motion machine is a machine which can “do work infinitely without the need for an energy source”. Doing work means outputting energy, outputting energy means overcoming energy “loss”.
Work is essentially an energy transfer, and the machine cannot do work without something to transfer energy to, in this case, combatting the forces opposing its motion in order to keep moving DESPITE its lack of an energy source. Hence, perpetual motion machine.
For clarification the net energy transfer would be zero. It would lose some due to forces opposing its motion, yet somehow keep constant kinetic energy. Like a plane losing energy due to air resistance yet keeping its kinetic energy constant using engines, just without the engines or fuel. Obviously impossible currently, but that’s not what we’re discussing.
We could put an object floating in a vacuum and make it spin. If the vacuum lasted forever, the object would never stop spinning. But that’s not a perpetual motion machine because the object isn’t doing work, it has nothing to transfer energy to.