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Gravity as a force

  1. Dec 8, 2004 #1
    Is fact or belief that gravity is a pull force? (in that we are pulled to the planets surface)

    I mean Newton saw an apple drop to the floor and thought pull?

    It could easily be a push force couldnt it, possibly a bit of both?
     
  2. jcsd
  3. Dec 8, 2004 #2
    How then would you explain the elliptical orbit of planets around other, large, ones?
     
  4. Dec 9, 2004 #3

    loseyourname

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    Planets exist because of the gravitational attraction between massive particles.
     
  5. Dec 9, 2004 #4

    Chronos

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    Gravity is attractive. There is a mountain of evidence favoring that conclusion and virtually no credible evidence to the contrary - at least on scales comparable in size to our solar system.
     
  6. Dec 9, 2004 #5

    krab

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    "Pull" and "push" are words we use to imply a relative position of our body when we exert a force. There is no physics in it.
     
  7. Dec 9, 2004 #6
    "Push" and "Pull" are formal concepts in physics, not informal, and refer to the direction of the force. Charges of the same sign push, those of different signs pull each other. So in the context of two masses interacting with each other the "push" direction is opposite to the vector from the center of mass of the body to the center of mass of the second body. The opposite is true for "pull".
     
  8. Dec 9, 2004 #7

    krab

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    That means pull and push are just other words for positive force and negative force.

    In reference to the original post, though, you see this is not the intended use. What is meant in regards to the falling apple is Is the apple pushed down from above or pulled down from below. I claim the distinction is meaningless.
     
  9. Dec 10, 2004 #8
    :smile:
    Attraction need not involve any 'force' perhaps.

    In William Gilberts original theory for magnetism at least attraction was a body's automatic response to signals from another body. No forces, just bodies responding to signals as robots respond !

    On gravity Newton was undecided between force and attraction. Einstein's theory of course built gravity into his spacetime continuum (as neither force or attraction ?).

    I know of only one new unverified website discussing this - http://www.new-science-theory.com
    :smile:
     
  10. Dec 10, 2004 #9

    ZapperZ

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    I am beginning to think that you own this site, which is why you are advertizing and citing it religiously as your primary source of info.

    Zz.
     
  11. Dec 10, 2004 #10

    Doc Al

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    I agree with Zz. That site has all the markings of crankdom. Why do you insist on referencing it? Please stop.
     
  12. Dec 10, 2004 #11
    DocA1 and ZapperZ,

    if either of you know a better website discussing alternative explanations of gravity (or other action at a distance) as 'attraction' or as 'force' or etcetera, then can YOU please give us that better website (or even journal reference). I would certainly much like to see it, though I can't find one.

    I have had my say on this and finished.
     
  13. Dec 10, 2004 #12

    ZapperZ

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    And as well you should already.

    You have got to be kidding when you're asking for "journal reference" for stuff on "gravitation". Either you are completely ignorant of the existence of physics journals, or you just don't care about them. Physical Review Letters, for example, has a WHOLE SECTION on nothing by Gravitation and Astrophysics. And PRL comes out once a week! How about reading up one of these every now and then? Or what about Physical Review D, in which the WHOLE JOURNAL is dedicated to Particle, Fields, GRAVITATION, and Cosmology? Never heard of that one either, eh?

    .. and there's MORE from where that came from.

    Zz.
     
  14. Dec 10, 2004 #13
    Your say was nothing but the link. :smile:
     
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