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Is it possible that the two bodies having same charge attract each other ?

  1. Jun 20, 2011 #1
    I have read in one book that it is possible if one body possess greater similar charge than other .:confused:
     
  2. jcsd
  3. Jun 20, 2011 #2
    yes it is possible but not of bodies of everyday size. The nuclear force is what make them do that, and it is dominant over coloumbic only when the distance is less than some threshold as in atoms. This force is effect of release of energy because of reduced mass resulting when nucleons come together. Recent research says they are the result of sharing mesons between nucleons.
    for more information I suggest feynman lectures chapter Basic forces
     
  4. Jun 20, 2011 #3

    ZapperZ

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    Not necessary if there are "assistance" from others. Look up "Cooper pairs" in superconductors.

    Zz.
     
  5. Jun 20, 2011 #4
    Suppose there is body A and body B of same size and both are having negative charge . They are separated by the distance of less than 35 cm . If body B has thrice the more quantity of charge as body A , will body B and A attract each other ?
     
  6. Jun 21, 2011 #5
    Unsure what "attract" means...but typical like charge is repulsive

    Not under normal cirumstances, but I can think of a few abnormal ones where they could attract:
    They are quantum particles and therefore anything that can happen will happen,
    They are rocketing towards each other at high velocity,
    They are weakly charged but massive, like black holes, so gravitational attraction will easily overcome weak electrical repulsion.....etc,etc
     
  7. Jun 21, 2011 #6
    You might find Wikipedia's discussion of "charge" helpful:

    http://en.wikipedia.org/wiki/Charge_(physics [Broken])
     
    Last edited by a moderator: May 5, 2017
  8. Jun 21, 2011 #7
    But what i have deducted a theory is this :
    F=Q*Q*R/T*D

    where d is displacement and T is time .


    Hence in case of body B The force of repulsion to body A is 3 times more . Hence it will repel body A (the whole body ) so the displacement would also increase three times ie not less than 105 cm . So they cannot be attracted to each other , maybe .
     
  9. Jun 21, 2011 #8
    Not only is that not dimensionally correct, it doesn't even make sense. How did you come up with that?
     
  10. Jun 23, 2011 #9
    BY applying certain mathematical deductions .
     
  11. Jun 23, 2011 #10
    Come on people. sankalpmittal asked a very simple question about basic electrostatics with macroscopic objects. Why are you talking about quantum effects?
    Of course two equally charged objects can attract under the right conditions.
    The same goes for magnets btw. If you take a strong magnet and a weak magnet and bring their north poles together, they will attract.
    Lets say you have 2 Objects - A and B. A is charged negatively and B is neutral. Now A will attract B. But what happens if you add a single electron to B? Then B will be charged but its charge will be so incredible small that it couldn't possibly change anything. So they still attract. If you keep adding electrons to B the attraction gets smaller and smaller and eventually turns into a repulsion.
     
  12. Jun 23, 2011 #11

    ZapperZ

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    Using "basic electrostatics", as you said, can you show mathematically how A can actually attract B?

    Zz.
     
  13. Jun 23, 2011 #12
    lol. Which one of you is planning on becoming a professor?
     
  14. Jun 23, 2011 #13
    I'm interested which book you read that in.
    Anyway, several of the answers point out when it can happen:
    1. On a nuclear level, the nuclear forces overcome the electromagnetic forces on short distances. Equal charges still repel but this force is then small compared to the the attractive nuclear force.
    2. Equal charges can be shown to attract as a result of some rather amazing quantum phenomena. In superconductors electrons form bound pairs because they exchange phonons - or, in other words, both interact with the lattice vibrations of a compound in a coherent way so that the net effect is an attraction. This attraction is somewhat abstract though since it is best understood in k and w space and more like a ring dance in ordinary space. A number of other mechanism can be shown to give attraction between charges, e.g. electrons. These electrons are then best understood as "pseudo particles", ordinary electrons with "dressed" properties so that they don't quite behave like ordinary electrons. The dressed properties can come from spin and magnetic interactions, polarizable media, dimensionality aspects, lattice vibrations etc - anything that can be excited and interact with the electrons in a coherent way. Often one refers to magnons, spinons, phonons, plasmons, anyons, holons when discussing such interactions. Some of these have been seen clearly in experiments and some just exist in theory. For more than 20 years scientists have been searching for the mechanism that make electrons "attract" in high temperature superconductor, but this mechanism is still not understood even though it is clearly seen in experiments!
     
  15. Jun 24, 2011 #14
    First contradict this :
    But what i have deducted a theory is this :
    F=Q2R/T*D

    where d is displacement and T is time .

    If charge is 3 times more in body B then

    Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .
     
  16. Jun 24, 2011 #15

    Drakkith

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  17. Jun 24, 2011 #16
    I already did. That equation doesn't have agreeing units - the left side is units of force, and the right side is in charge2 per second. The units don't agree.

    Also, you never explained what you mean by "T is time." Time of what? The time between what two events? You never explained what "R" is supposed to represent either.

    Explain how you came up with that (absurd) equation, detailing your logical process.
     
  18. Jun 24, 2011 #17

    ZapperZ

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    Please note that, if you're making things up on your own, you are making speculative post, and in violation of the https://www.physicsforums.com/showthread.php?t=414380" that you had agreed to.

    We will let you continue with this thread if there are indications that you wish to learn. You can show this by addressing the issues brought up by Superstring. However, if you continue to produce your own "deductions", this thread will end!

    Zz.
     
    Last edited by a moderator: Apr 26, 2017
  19. Jun 24, 2011 #18
    I was just making myself satisfied if the deduction is correct .
     
    Last edited by a moderator: Apr 26, 2017
  20. Jun 24, 2011 #19

    ZapperZ

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    But you ignored the obvious mistakes that have been pointed out!

    Zz.
     
  21. Jun 24, 2011 #20
    F=Q2R/T*D

    where d is displacement and T is time .

    If charge is 3 times more in body B then

    Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .

    T represents the time taken by electrons on body A to repel to opposite extreme ends . R is the resistance faced by the e-1 while moving to the extreme ends .(different in different materials )

    My deductions however may be wrong .

    I never ignored my obvious mistakes . I never said my deductions have to be correct .
    I confess , it may be wrong .
     
    Last edited: Jun 24, 2011
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