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Author Topic: Is there a Third-Law Reaction Force on the Magnet?  (Read 626 times)
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  Gents,

   I have a serious question for you.
Consider the Lorentz force (red in the Figure) on a wire segment, where the magnetic field B is produced by a permanent magnet (blue, cylindrical and sitting in the "wrist position.").  Assuming the B field is approximately uniform across the short wire , then the Lorentz force equation is as shown (F = Il X B, vectors, so direction is given by the right hand rule as shown in the Figure below).

   Now my question is this:  Is there an Third-law Reaction Force on the Magnet,  equal-but-opposite to the force on the wire?  How do you know?
Please do not just give a naive application of Newton's Third Law...


Figure credit (then I modified the Figure):  https://en.wikipedia.org/wiki/Lorentz_force

   
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  Note that when two magnets approach with N facing N, there is indeed an "equal-and-opposite" force on each - and these "repelling" forces are PARALLEL to the field lines from each magnet.
 
  Contrariwise, in the case of the Lorentz force on the wire segment (above), that force is PERPENDICULAR to the B field.  It is not clear in that case that there is a Third-law-reaction force...   but you tell me. 

   If there is no reaction force...  later on that.
   

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I recently read wht little I could find on the work of Martin N. Kaplan, who was a research engineer at Ryan Aeronautical in the 1960's. 

Very few scant details are available, but he was convinced that the homopolar motor with a magnetic rotor, pushed on the magnetic field itself, or magnetized space.  He believed one could produce a gravity-like force and push on space as a means of propulsion,  Even though he stated he had successful experiments, only some early work is available.

Based on, this and you example with the magnet and wire, it seems safe to say that fields with react with like fields.  So the magnetic field of the induced curent in a wire will react with the magnet field inducing it. (Lenz's Law?).

I can post what I have on Kaplan if you like.

Kaplan's conclusion makes propulsion very nice if we could produce an accelerating force like gravity.  This is the same conclusion Paul Hill came to after 20 years of real UFO research and analysis.  However, I don't think either of these gentlmen found a way to produce the necessary accelerating force.

   
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I recently read wht little I could find on the work of Martin N. Kaplan, who was a research engineer at Ryan Aeronautical in the 1960's. 

Very few scant details are available, but he was convinced that the homopolar motor with a magnetic rotor, pushed on the magnetic field itself, or magnetized space.  He believed one could produce a gravity-like force and push on space as a means of propulsion,  Even though he stated he had successful experiments, only some early work is available.

Based on, this and you example with the magnet and wire, it seems safe to say that fields with react with like fields.  So the magnetic field of the induced curent in a wire will react with the magnet field inducing it. (Lenz's Law?).

I can post what I have on Kaplan if you like.

Kaplan's conclusion makes propulsion very nice if we could produce an accelerating force like gravity.  This is the same conclusion Paul Hill came to after 20 years of real UFO research and analysis.  However, I don't think either of these gentlmen found a way to produce the necessary accelerating force.

I would be interested in what you have on Kaplan, thanks.

" So the magnetic field of the induced curent in a wire will react with the magnet field inducing it."

   The magnetic field of the current flowing in the wire forms circles around the wire, shown in the attached.  Thus, two current-carrying wires attract each other. 
   But this is NOT the situation in the example I showed - with just ONE current-carrying wire pushed at RIGHT ANGLES by a permanent magnet.
 
Also, the current in the wire is NOT induced in it by the permanent magnet (initial post).
   
   

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Ok, in your example the wire is carrying a current, and the magnet is fixed.

The wire experiences the Lorentz force per your example.

Your question: Is there a force on the magnet equal/opposite to the force on the wire?

I think the curent carrying wire pushes against the magnetic field in space.

It may be more accurate to state:
the magnetic fields of the moving electrons in the current carrying wire push agianst the magnetic field in space produced by the magnet.

So fields react with like fields, in simple terms.

I wonder if there is a torque applied to the wire as well...or just the orthogonal force

   

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I posted everything I have on Martin N. Kaplan here:
https://www.overunityresearch.com/index.php?topic=3889.msg79958#new

   
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I posted everything I have on Martin N. Kaplan here:
https://www.overunityresearch.com/index.php?topic=3889.msg79958#new

Thanks, Grumpy.
--Steve
   
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  After several tries, I was able to pose my question on Physics StackExchange.  See screen copy below.
(Note that my submission would not work when I tried to attach the figure shown in my post 1 above.)
   
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  I edited the question for clarity, corrected posting follows:
   
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   Chet notes that this thread is "invisible" when logged in - and I had the same problem.  But I could see this thread when logged out, then I logged back in and
VOILA
it now appears again in the Index.

Can you see it now, Chet?
   
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Going back to the original question, NO,  there is not an equal but opposite reaction force.  There is a torque on the magnet that tries to align it with the tangential magnetic field from the magnet.  This is not the only case where Newton's Law is violated for current elements.  A current element radially orientated to a long  current carrying wire will endure a force due to the field from the current, but there is not a linear force on the wire.  There is a local torque on the wire.  This deviation from Newton is usually explained by the fact that you cannot have an isolated current element, the current must arrive from somewhere and go somewhere.  When you take into account the entire current circuit (even if it goes to almost  infinity) then Newton's Law is satisfied.  If you have an isolated moving charge as the current element then it receives the Lorentz force without that same reaction force on the magnet.  This suggests that an electric dipole shaped like a dumbbell driven with alternating current would receive an alternating force from the magnet,  with no equal reaction on the magnet.  Don't know what use that would be.
Smudge
   
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  I can now access this thread OK while logged in and make a REPLY - a big improvement from yesterday.
  However, I still cannot "see" this thread on the Index page - it does not appear while I'm logged in.  I have stored the link, and can access this thread while logged in by clicking on that stored link.
   
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 Testing - yes, it seems back to normal now. 
Thank you, Peter.
   
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...If you have an isolated moving charge as the current element then it receives the Lorentz force without that same reaction force on the magnet.  This suggests that an electric dipole shaped like a dumbbell driven with alternating current would receive an alternating force from the magnet,  with no equal reaction on the magnet.  Don't know what use that would be.
Smudge

An isolated moving charge is not a physical situation, because each moving charges influences the charges in the environment and thus changes their distribution. A moving charge is always a looping current through the displacement current.
In order to make the balance of forces in an interaction including the Lorentz force, one is thus obliged to make the calculation on the whole circuit, that of the current but also that generating the magnetic field. It's known that the quantities are conserved (momentum and angular momentum, energy).

But it is not simple to calculate. For example in this thought experiment, I had wondered why we would not have a net force on this square loop where a generator induces a current, because the Lorentz force, due to the current in its own magnetic field, can no longer be exerted in the part of the space between plates of the capacitor. I don't have the answer.


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"Open your mind, but not like a trash bin"
   

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Of course, we can't have a reaction against empty space.
That would be absurd...
   

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A Manifest Failure of Grassmann’s Force

(see attached)
   

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Electromagnetic Propulsion of Matter in Violation of Newton's 3rd Law:

(attached)
   
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Grumpy
Quote
Of course, we can't have a reaction against empty space.
That would be absurd...

There are several problems with your statement.

First, we have known that space is not empty from decades of science experiments proving this is not true. In fact Feynman/wheeler calculated that there is enough energy in the vacuum inside a single light bulb to boil all the world's oceans. Ergo there is no such thing as "empty space".

Second, the Casimir effect not only proves space is not empty but also that the energy in this space can apply a force to material things such as two plates causing them to move or react with said space. If "space" can act on material things and we know as a fact it can then it is extremely probable that we will eventually understand how to act on space to produce a reaction/propulsive force.

We know as a fact that space is a sea of energy as high energy particles and Electromagnetic waves thus the only real problem is how we interact with what is already present in space to produce a unidirectional force or reaction as you say.


---------------------------
"Great minds discuss ideas; average minds discuss events; small minds discuss people." - Eleanor Roosevelt.

Be careful when you blindly follow the Masses... sometimes the "M" is silent.
   

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I was being sarcastic.

Sarcasm: the use of irony to mock or convey contempt.

It's easy to prove that you can push against space if you agree that a manetic field resides in said space.

That doesn't equate directly to a means of propulsion, however.

Until we understand how gravity is produced and have the skills to produce a gravity-like force, we will be sitting right here in this solar system.

   
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  I understood your point as sarcasm, Grumpy.

"It's easy to prove that you can push against space if you agree that a magnetic field resides in said space."

   I wish it were that easy to prove!  I'm working on it...
   

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If a magnet field resides in space, then two magnets pushing against each other are both pushing against the magnetized space, so-to-speak.
   

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If one argues that as magnet pushes or pulls on another magnet, then why do the field vectors change in space?

   
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