# Thread: Are opposite forces the same?

1. ## Re: Are opposite forces the same?

Originally Posted by Eleftherios Karagiannis
Thank you for taking the time to explain it. I don't understand it, but others do or could, and that is great.

How can opposite forces move an object in the exact same way? The only difference I see is perception, not the way the object moves.

If you were watching the table and could not see the people, how could you tell which force is which? The object moves exactly the same, in both cases, when in reality opposite forces were applied. That is why I believe the force is the same and the only difference is perception, which is not a force.

If you explained that already, I apologize. Again, thank you.
Newton's Laws depend on the idea that the light with which we observe objects do not interfere with the motion of objects on our perceptual scale. That is, the objects would still be moving even if we were blind. They only change their motion via interaction.

Energy (work) = Force*distance; e.g., for a unit distance (where the objects move a unit distance under a given force), and equal and opposite interaction, E2 = F2 (since both negative and positive forces are involved. Again, there are the three possibilities above, which would happen even if one was blind. (This isn't a complete classical description, since the work is virtual, but it does illustrate the basic idea involved.." (virtual work)

However, on a microscopic scale, the contact interaction is electromagnetic in nature, and ultimately quantum mechanical, which requires a different analysis (which you can't see just by watching objects collide). Since you can't see interactions at this level, the analysis is determined experimentally, and the relation is affirmed for large objects via the Bohr correspondence principle (microscope analyses correspond to classical (Newtonian) physics in the case of large quantum numbers. (Acoustic virtual deformation of quantum lattices - i.e , solid state physics).

The latter analysis is the basis of theoretical physics from the late 19th century on... (starting with Ampere, Coulomb, Faraday, et. al., through Maxwell, to Eintsein, Bohr, Heisenberg, Dirac, Feynman, and beyond - it is not trivial.... (That is, one really needs to "do the math"...)

2. ## Re: Are opposite forces the same?

Originally Posted by BuleriaChk
(That is, one really needs to "do the math"...)
And that is where my problems begin. I am still stuck on 1+1 and 1-1. You have given me much to learn, and great places to start. Many will benefit. Thank you very much.

3. ## Re: Are opposite forces the same?

Originally Posted by Eleftherios Karagiannis
And that is where my problems begin. I am still stuck on 1+1 and 1-1. You have given me much to learn, and great places to start. Many will benefit. Thank you very much.
You're certainly welcome. Remember, Google and Wikipedia can be your best friends in your search, even though they are sometimes intimidating (there has been a lot of intense work by brilliant minds over the past two centuries, at least). But it is the journey itself that is rewarding....

4. ## Re: Are opposite forces the same?

Originally Posted by BuleriaChk
You're certainly welcome. Remember, Google and Wikipedia can be your best friends in your search, even though they are sometimes intimidating (there has been a lot of intense work by brilliant minds over the past two centuries, at least). But it is the journey itself that is rewarding....
Could not agree more, much confusion, frustration, failure, to name some, lead to the path of success, eventually. Time, trying and chance, my favorite.

5. ## Re: Are opposite forces the same?

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

When one body hits another body, is there no loss of force due to friction?

If I am pushing you with 10 pounds of force, and you me with 12 pounds of force, I am -2 and you are +2. But that is only the describing the difference not what we are.

Add a third person, they push me with 8 pounds, me pushing you with 10 and you me with 12. Now what? Am I +6? I can see that, but I am still 10. If my force did not change, how could I change from a negative to a positive force?

If I am pulling you with 10 pounds of force and you are pushing me with 1 pound of force, am I negative or positive?

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