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What is the relationship between physics field and force?

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  1. Feb 15, 2016 #1
    Whenever there is a field there will be a force whenever the field interacts with an object placed in that field?

    Is this always correct?
     
  2. jcsd
  3. Feb 15, 2016 #2

    phinds

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    One thing that occurs to me in this regard is that gravity is a field in classical physics and involves a force, but in GR it's just a result of space-time geometry and no force.
     
  4. Feb 15, 2016 #3
    Field is a mathematical object which has a value (scalar or vector) at every point in space (or some manifold).
     
  5. Feb 15, 2016 #4
    It seems redundant but it was actually a real step forward in understanding when the concept of the field took hold. The story goes that Faraday had the intuition for fields and Maxwell made them mathematical. Prior to fields, forces were thought to "act at a distance," which was another way for saying that we didn't have a clue what was going on, but surely something. Taking the idea of fields seriously, by which I mean thinking of them as actual physical entities rather than mere mathematical abstractions, was a necessary step towards Maxwell's derivation of the self-propagating electromagnetic wave. There is just no way to talk about radiation if you only have the concept of force, and no fields. So while it may seem redundant for certain applications, it was a real step forward for our understanding of physics, the story goes.
     
  6. Feb 16, 2016 #5

    HallsofIvy

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    If the field is a force field then, pretty much by definition, if an appropriate object is placed in the field, there will be a force on it- but there are many kinds of fields other than "force" fields. The reason I say "appropriate" object is that there are many different kinds of force fields. Any object with mass will feel a force in a gravitational field but only an object with charge will feel a force in an electric field (and only a moving object, with charge, will feel a force in a magnetic field).
     
    Last edited: Feb 16, 2016
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