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Center of Gravity - Laws and Explaination

  1. Jun 25, 2014 #1
    This is my first thread, and I am excited to post it.:biggrin:
    My question is that, did any Scientists do any research about Center of Gravity and formulated any laws or gave explanation to it's fundamental behavior? If so, then have they considered the Center of Gravity of liquids and semi-solid objects?
     
  2. jcsd
  3. Jun 25, 2014 #2

    A.T.

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    What "fundamental behavior" do you mean? The definition of "objects" is rather arbitrary and the center of gravity can be computed for any arbitrary collection of point masses.
     
  4. Jun 26, 2014 #3
    I think you don't understand the question. I asked for any scientists who made any research on COG.

    If you can calculate the the COG for any arbitrary collection of point masses, then can you calculate the point masses of fluids and semi solids?
     
  5. Jun 26, 2014 #4

    A.T.

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    You can calculate the COG for fluid bodies, or arbitrary parts of them.
     
  6. Jun 26, 2014 #5

    SteamKing

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    Since fluid takes the shape of its container, the c.o.g. of the fluid will be the same as the center of volume of the container below the liquid level.

    Engineers calculate the c.o.g. of fluids in containers every day. It's a standard calculation for naval architects and any other engineers involved with stored fluids. I don't see any big mystery here. Probably the last scientist involved with c.o.g. 'theory', if there is such a beast, was Isaac Newton, who enunciated the concept of a c.o.g. in the first place. There might have been one or two naval architects involved later when that discipline was being put on a scientific foundation, but that was just adding different applications for which the concept already existed.
     
  7. Jun 26, 2014 #6
    Then how about these observations?

    COG:

    1.Every particle in an object consisting of more than one
    particle bonded by enough force exhibits the property of
    normalizing their respective gravitation of each and every
    individual particle by their relative position to one another
    to a well defined area in space.

    2.This defined position in space represents and reflects the
    gravity of all the particles in the object.

    3.An object will be considered to be stable, (having 'n'
    particles in its domain), if and only if, the change in
    physical parameters such as heat, vibration, impulse or
    change in momentum does not being about the reduction in any
    part of the 'n' particles from the domain of the object and
    their relative position to one another.(although this is
    non-practical, values may vary)

    4.The defined part of space of the object acts as the center
    point for all the external or internal changes that may
    occur to the object, in which any change in the number of
    particles, their relative position and the influence by any
    internal and external forces will be reflected immediately
    upon that particular region of space.

    5.This well defined space varies from object to object,
    depending upon their count for particles and their relative
    distance from one another.

    6.This space might occupy a singular point in most stable
    objects; a straight line in objects under angular
    displacement; a two dimensional area of well defined
    boundaries in case of multi stable objects; a three
    dimensional area having stable or dynamic boundaries in their
    space.

    7.Each and every object is bound to this space to an extent
    such that, any linear or angular changes in momentum caused
    by both internal and external influences will be reacted
    directly from and about this region of space.

    8.Any external impulse will cause the object to rotate with
    an angular momentum proportional to the impulse and a line
    passing tangentially throughout this region of space as it's
    axis of rotation in free space, void of any other external
    forces or forces with relatively small influence.

    9.Any object that is in free space can rotate in two axes
    simultaneously, both passing through this region of space, in
    which both the axes coincide with one another at this
    particular region of space.

    10.An object that has definite number of particles in it's
    domain and a definite relative position of the particles in
    the domain is said to be stable under standard internal and
    external influences.

    11.An object having definite number of particles in it's
    domain but has a dynamic relative position of the particles in
    the domain is said to be dynamic under standard internal and
    external influences.

    12.A stable object is likely to have a well defined region in
    space while a dynamic object will have a more complex and
    irrational region in space and will vary with each and every
    relativistic change in the position of the other particles.

    13.Two different objects with comparatively different defined
    regions in space can be bound together into a single stable
    object by atomic or molecular binding forces such that their
    resulting region of space will be exactly in the middle of
    the line joining their respective spaces. For two stable
    objects, it can be a two or three dimensional region in space
    while for dynamic objects, it could be a dynamic region of
    space, that changes with the relative change in either one of
    the dynamic objects.

    14.Such a region in space possessed by an object is termed as
    "Center Of Gravity" or COG for short.
     
  8. Jun 26, 2014 #7

    SteamKing

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    Well, if you like overthinking a simple concept, Post #6 ought to get a Noble Prize, or an Ignobel Prize.

    To determine the c.o.g. for most things, it's more a matter of geometry than any particularly deep thinking.

    To paraphrase Borek, Post #6 is a 14-course 'word salad'.
     
  9. Jun 27, 2014 #8
    Thank you for your reading and reply of the "simple concepts". COG is not just a matter of geometry, but involves the bonds that exists between each and every particle, and also the nature of the bonds and it gets more complicated if non-homogeneous objects are bought into consideration.

    Yes, I like over thinking a simple concept, like Newton who obsessed with an apple which fell on his head. By the way, COG is simple to our view because we experience it within the Earth's gravitational field. You have no idea what will happen when complex objects behave in space...
     
  10. Jun 27, 2014 #9

    A.T.

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    Newton wasn't over thinking but rather simplifying things by introducing a simple and universal law of gravitation.
     
  11. Jun 27, 2014 #10

    SteamKing

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    I'm afraid you need to cite some scientific paper or study to provide a foundation for these assertions.

    I sorry to disappoint you, but 'bonds' have nothing to do with determining the c.g of an object.
     
  12. Jun 27, 2014 #11

    Doc Al

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    In a uniform gravitational field, center of gravity is the same as center of mass.

    But neither has anything to do with the internal forces or bonds within an object. All that matters is the mass distribution.
     
  13. Jun 27, 2014 #12
    Yeah, well if I had found any scientific paper that provided a foundation for these assertions, I wouldn't be here.

    I am sorry to disappoint you too, but they do play a role in determining the COG of an object.

    If you still don't get a picture, imagine you have a stick. A long stick and you are holding it in your hand vertically. You can find the COG of the stick, it'll be right in the middle of it.Now, as you are holding it, one arbitrary portion of the stick gets weak and the rest of the stick begins to break apart slowly. Now where do you think the COG will be?
     
  14. Jun 27, 2014 #13
    Yes, he clearly was over thinking instead of just eating the apple. In fact, he wouldn't have even thought about "simplifying" even though, he did no experiments, just an object fell over his head.
     
  15. Jun 27, 2014 #14

    Doc Al

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    As long as the mass distribution remains the same, so will the COG. If the mass redistributes, the COG will change accordingly.

    You need to understand how COG/COM is defined.
     
  16. Jun 27, 2014 #15

    Doc Al

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    I think you can stop comparing yourself to Newton. :smile:
     
  17. Jun 27, 2014 #16
    Black holes get changed in their internal symmetry due to gravity.If that's too easy, consider the sea. It is in an uniform gravitational field, but you have no idea of center of gravity or center of mass.

    I am trying to understand gravity in a whole new level... not just mass, not just symmetry, not just the bond or it's nature, not just about the object itself even though how much complicated it is.

    We cannot apply the standard center of mass and center of gravity calculation to all objects in the universe. Each and every single particle in the atom which determine it's characteristics contribute to the nature of the object. We cannot conclude into discarded and unexplored parts of science because it is redundant...
     
  18. Jun 27, 2014 #17
    Do you have an imaginative mind? btw, I am not Newton and am not comparing him with me...
     
  19. Jun 27, 2014 #18

    Doc Al

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    Sounds like you are not interested in mainstream science, but in your personal theories. That is a violation of our rules.

    On that note, this thread is closed.
     
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