Energy released by strong force

Discussion in 'Physics & Math' started by granpa, Jun 28, 2016.

  1. granpa Registered Senior Member

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    350
    a chemical reaction might release 10 ev of energy.
    a nuclear reaction releases millions of times that.
    we are told that that is because the nuclear force is much stronger.
    At first that seems to make perfect sense but upon closer inspection the numbers clearly dont work out.

    The strong force is only 100 times as strong as electromagnetism and it only acts over a very short distance (about the size of the nucleus or 1/10,000 of an angstrom)

    now energy = force * distance

    so 100 * (1/10,000) = 0.01

    even though the force is stronger it should release much less energy.
     
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  3. Fraggle Rocker Staff Member

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    And since this is NOT what happens in reality, you must have made an error in your calculations.
     
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  5. exchemist Valued Senior Member

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    You appear to be out by a factor of 10: http://scienceworld.wolfram.com/physics/FundamentalForces.html

    And I think you might want to take a look at the section of this article on Energetics: https://en.wikipedia.org/wiki/Nuclear_fission

    The strong force holds the nucleus together but once the nucleus is sufficiently deformed against the attraction of the strong force, it flies apart by electrostatic repulsion, i.e. the energy release in fission comes, not from the strong force, but from the electromagnetic force. It seems to be like a compressed spring held by a catch. The strong force is only the catch, not the spring.

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    Or that at least is my understanding.
     
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  7. granpa Registered Senior Member

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  8. granpa Registered Senior Member

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    Angular momentum of electron = (planks constant)/(2pi)
    Relativistic angular momentum = γmvr
    Relativistic centripetal force = γmv^2/r

    Gamma*(electron mass)*c*(10^-14 m)=(planks constant)/(2pi) solve for x
    Wolfram says gamma = 38.6

    38.6*(electron mass)*(velocity of light)^2/(10^-14 m)
    Wolfram says force = 316 newtons

    The force between 2 electrons at that distane is
    ( Coulomb's constant )*(electron charge)^2/(10^-14 m)^2
    Wolfram says 2.3 newtons

    According to those equations the force is 137 times stronger than electromagnetism would be at that distance and that is sufficient for the electron to fit inside a neutron
     
  9. granpa Registered Senior Member

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    350
    The key phrase is "at that distance"
     
  10. exchemist Valued Senior Member

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    What's your point? Wolfram is wrong? Physics is wrong? Or are you saying there is something you don't understand? Or something else entirely?
     

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