# How to improve my model

Discussion in 'Physics & Math' started by Thinh Nghiem, Sep 29, 2016.

1. ### Thinh NghiemRegistered Member

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4
Hi all,

Could you look at my model in

with description below and give me feedback of how to improve so that it can spin longer? Thanks

3. ### exchemistValued Senior Member

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7,337
No. If you can explain, in words, what you are doing and what help you need then maybe. But I'm not wasting my time watching amateur YouTube videos.

And this time it had better not be perpetual motion.

Russ_Watters, sideshowbob and Dr_Toad like this.

5. ### Thinh NghiemRegistered Member

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4
My system consists of 2 elements. Each element is a cylinder put on an axle. There are two permanent magnets stuck on the cylinder, with their north pole are faced outside.
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.

I would like to emphasize that I do not have intention to invent any perpetual motion. My system will stop finally. What I want to do here is how we can improve this model so that it can rotate longer, for example 15 minutes. We will gain much of work or energy by this.

Thank you

7. ### Dr_ToadIt's green!Valued Senior Member

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Really, he did. Dear God. Another one...

8. ### exchemistValued Senior Member

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You won't gain any work or energy by this.

When you line up your cylinders with the magnets opposing each other you do work on the system, which goes into the stored energy represented by the magnetic repulsion.

This energy is released when the cylinders are allowed to rotate and is converted to kinetic energy.

If your bearings were frictionless and there were no air resistance, the motion would continue indefinitely. But your bearings do have friction and there is air resistance, so the motion eventually stops, once all the kinetic energy is converted to heat.

If you want the motion to continue longer, use better bearings and cylinders that have lower surface area for air resistance. The ones you have here look like lampshades.

9. ### UltronRegistered Senior Member

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Why do you want to rotate it longer? Whats the difference if it rotates 5 or 15 minutes?

10. ### DaeconKiwi fruitValued Senior Member

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You won't gain any work or energy at all.

11. ### sweetpeaValued Senior Member

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Do away with the magnets and suspend each drum by a cotton thread. Wind-up threads and let both spin...Trouble is, they will spin too fast.

12. ### sideshowbobSorry, wrong number.Valued Senior Member

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You're not gaining anything. You're only storing the energy that you put into it to start it moving. And making it spin longer only decreases the rate that you can take energy out of storage.

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14. ### danshawenValued Senior Member

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3,950
Perpetual motion machines do not exist, but there are many fakes on the internet that last for longer than 15 minutes (with fresh batteries installed, that is).

So, what is really the point of extending yours?

Last edited: Oct 13, 2016