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B Perpetual machine

  1. Feb 14, 2017 #1
    Hey, I'm new on the forum and I have a pretty basic understanding of physics, I hope this question isn't obvious I just need some help getting my head around it.

    I was reading up on the problem with gravity of a means of generating perpetual energy, the fundamental problem being that gravitational potential energy is only generated through the original force required to separate an object from the centre of a gravitational field. Which of course is always more than the energy that can be harvested from the attraction.

    However what if you had an incredibly dense ball of matter that was stable and undergoing no atomic or molecular change, the opposing forces would generate thermal energy indefinitely no? Surely the opposing forces of the rapidly vibrating atoms and the infinite pull of gravity would create energy without consuming mass?
  2. jcsd
  3. Feb 14, 2017 #2
    FYI, perpetual motion machines is not a permitted subject on this forum. For the reason that it violates the conservation of energy, a physical law that has never been observed to be violated, in hundreds of years and millions of experiments. Energy does not get created, or destroyed. Ever.
    What's usually violated is thus the understanding of physics of the person trying to build one.
  4. Feb 14, 2017 #3


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    Staff: Mentor

    Welcome to the PF. :smile:

    As already pointed out, PMMs and Free Energy are banned topics here. Please follow the links in the quote from the PF rules below to learn more about why they cannot work.
  5. Feb 14, 2017 #4


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    Staff: Mentor

    I know it is locked, but a couple of quick notes:
    Be careful where you are reading-up on it: my thermodynamics book has a section on perpetual motion -- that's good. Youtubue videos, bloggers, PMM companies? Often not good.
    Two things:
    1. Force isn't energy. Energy (work) is force times distance. So an object sitting still in a gravitational field is not generating or consuming energy.

    2. Thermal motion of atoms in an object is perpetual, but it isn't consumed or produced: it is constant. So as you try to harvest it (by using it to heat something), the energy is consumed. So you cannot use an object's thermal energy for continuous energy production.
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