Energy conservation violation

First of all, I would like to say that this model is NOT a perpetual motion. It will stop eventually. What I want to say here is that the output useful work seems to be greater than input energy

My system consists of 2 elements. Each element is a cylinder put on an axle. There are two permanent magnets stuck on each cylinder, with their north poles are faced outside. In the youtube clip that I will show you below, you can see the magnets of the first element are painted in blue, while those of the second one are crossed with X.

I turn the cylinders slightly so that the north poles of the magnets are faced each other. Then, the thrust between magnets make the cylinders rotate.

A single cylinder on an axle itself is not the system. It is an element of the system, which consists of 2 at all. Therefore, the thrust between magnets is not external force which affect system. It is comprehended as internal force between 2 elements of the system. The thrust from the first cylinder makes the second rotate, and the thrust from the second, in its turn, make the first rotate. Each component act as the cause to make the other rotate, and it acquires the affect from the other to rotate.

While the input work of the system originates from a small force making cylinders moving short arc, and make magnets facing each other, the output dynamic energy is much higher. You can see in the clip that both cylinders rotate many circles, which create output useful work much greater than the work to make the magnets facing each other.


Here is the link of my clip




Your comments are welcomed to determine that if energy conservation is violated in this case or not

Thanks

Thinh Nghiem from Vietnam

Replies

  • Shashank Moghe
    Shashank Moghe
    Not violated. You are right about the forces being internal forces. In this case, internal energy of the system is used to do work. Remember, magnets do lose their magnetism over time. It is this energy at the expense of which this work is done.
  • Thinh Nghiem
    Thinh Nghiem
    I simply estimate like this

    Input energy came from the force of my hand to turn the cylinders so that their magnets face each other.

    And the output work results from the rotating many rounds of the cylinders, which is much greater than my input work

    What happen if I can improve my model, so that the rotating can last at least 5 minutes ?
  • Shashank Moghe
    Shashank Moghe
    Well, the extra force required beyond what your hands applied derives energy from the magnetism of the magnets (that is the internal energy of the system). You cannot neglect that. Hence energy conservation law is not violated.

    No matter how much longer you make the rotating last, it will still derive from the internal energy of the system and the energy conservation law will never be violated.
  • Thinh Nghiem
    Thinh Nghiem
    But at least it is helpful in technical. I have plan to improve my model so that it can rotate longer, for example 1 hour. Do you think it is economical. It can be used in a rotor of a generator. We do not need fuel, just our manual force, and the rotor will spin for a long time to generate current. Is it OK?
  • Shashank Moghe
    Shashank Moghe
    Well, it will always try to come to a deadlock (equilibrium position), after which the assembly does not rotate. So not only will it have motion which is retarding with time, it will not be close to the rpms you need to have in your rotors to generate electricity.

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