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How strong is the strong force?

  1. Sep 25, 2014 #1
    I got to wondering about this the other day so I tried looking it up but I could not find anything. All j could find was that it had a maximum force of 10,00N. I tried to calculate the electrostatic force of a helium atom because if the strong force has to hold the atoms nuclei together jt has to be at least in equilibrium with the electrostatic force, but tbat came up to be 230.4N. So now I am left with 230.4<FS<10,000. How do I calculate the actual strong force or did I miss something or what? Thanks for the help!
  2. jcsd
  3. Sep 25, 2014 #2


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    yes, that the "force" as a "force" is meaningless for quantum particles.
  4. Sep 25, 2014 #3
    What is my misunderstanding then? I thought the string firce was what held the particles together against the repulsive electrostatic force
  5. Sep 25, 2014 #4

    Vanadium 50

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    The strength of the strong force, in newtons, is not a fixed number, just like the strength of the electrostatic force. It's a rather more complicated function than the Coulomb function, and you can find a simplified graph at http://en.wikipedia.org/wiki/Nuclear_force
  6. Sep 25, 2014 #5


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    I'd say that you don't have a string force....In general I am not finding the concept of "force" helpful in quantum mechanics, neither in QFTs. In both cases the potentials work better, since they are directly connected to energy. Then this "hold together particles" are described by "bound states". rather than "cancelling forces".
    The cancelling forces for example, for what I think at the moment, requires to have a localized particle at some distance and thus calculate a force... However the particle can be not localized (in an energy eigenstate rather than in a position one).
    Finally the nuclear potential is rather a complicated structure, it contains many terms some coming from theory and others from experiment, with many parameters which are determined experimentally and so on... there can be 14 terms (older Argonne potential) and so on.

    Also you can see that coulomb is not enough if you try to think for why there is no bound state of neutron-neutron (no coulomb interaction between each other)
    Last edited: Sep 25, 2014
  7. Sep 26, 2014 #6


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    You can't really assign a fixed number, like Vanadium 50 said, but what you can do is compare the relative strengths of the fundamental forces in QFT with something called the coupling constant. Then, you can say that (approximately), the strong force is 1038 times stronger than gravitation, and the electromagnetic force is 1036 times stronger than gravitation (and weak is 1025 times stronger than gravitation).

    Calculating the behaviour of nucleons interacting through the strong force is the domain of Quantum Chromodynamics.
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