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As I was reading a intermediate part-2 book I come to know that self-perpetual system is not possible. So i wanted to know if it is possible or it's completely impossible.

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    $\begingroup$ See en.wikipedia.org/wiki/Perpetual_motion $\endgroup$
    – Curious Fish
    Nov 15, 2018 at 20:24
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    $\begingroup$ Additionally, according to the same article, "Perpetual motion is motion of bodies that continues indefinitely. A perpetual motion machine is a hypothetical machine that can do work indefinitely without an energy source. This kind of machine is impossible, as it would violate the first or second law of thermodynamics." $\endgroup$
    – Curious Fish
    Nov 15, 2018 at 20:25

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It is very important to distinguish between perpetual motion and a perpetual motion machine.

Perpetual motion is the natural state of all objects. Newton's First Law states that an object in motion will remain in motion - forever.

A machine does work. Ultimately in this case, that means providing force. So by definition, an object doing work cannot be in perpetual motion.

It really is pretty much that simple, you can add the 2nd law on top if you wish, but it's self-evident from Newton that the concept is problematic.

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  • $\begingroup$ But I think it is possible. In the case of electric motor we give maniacal energy it produce electric energy if we convert that energy and give electric motor. The electric motor move freely.Is it possible ? $\endgroup$
    – Raja Ali Haidar
    Nov 15, 2018 at 21:32
  • $\begingroup$ No. All such systems have losses. There is no such thing as a lossless system. In this case you have efficiencies of the motor that are well less than 100%, and resistance in the wires. So the motor will slow down and stop. Quickly. $\endgroup$
    – Maury Markowitz
    Nov 15, 2018 at 21:35
  • $\begingroup$ @RajaAliHaidar Even if you aren't convinced by Maury Markowitz's answer (why not use superconducting wires with no resistance, for example?) any electrical machine with moving parts or varying current is effectively a radio transmitter, and will radiate some energy into space as electromagnetic waves. $\endgroup$
    – alephzero
    Nov 15, 2018 at 22:13

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