Gravity Law

  1. As gravity law says: F=G( (m1*m2)/r^2).
    That means that power between two objects with more mass is biggest.
    Why? It is because they have more atoms?
    Thank you.
     
  2. jcsd
  3. Vanadium 50

    Vanadium 50 17,755
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    Chegg
    Power is wok per unit time. Power is not in your equation.

    You probably mean something else, but in science you have to be very clear about what you mean. Otherwise we have to guess.
     
  4. What you mean?? F does not mean power? Is not the power that a object attract an other??
     
  5. cepheid

    cepheid 5,194
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    No, F does not mean power. F means force. In physics these words have very specific meanings. Force is a different quantity from power. You cannot use them interchangeably.
     
  6. Ok then,I am sorry.
    So you can answer me?? Why object with more mass have more force than other objects with less mass?
     
  7. cepheid

    cepheid 5,194
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    Also, there is no good answer to your original "why" question other than, "Because that's what we observe to be true." That's how gravity works in nature. Objects with more mass have more gravity.
     
  8. I think that the answer is,because objects with more mass make bigger curvature in the space time(about general relativity),so biggest curvature means bigger force
     
  9. ZapperZ

    ZapperZ 30,004
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    Then I could play your game. I can ask you "Why do objects with more mass make bigger curvature of space time?"

    Now what?

    Zz.
     
  10. That is what I try to find now. If anyone knows let me know.
    (Also I am not playinh any game,I just want to udnestand the universe.)
     
  11. ZapperZ

    ZapperZ 30,004
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    Well then, you shouldn't be using the curvature of spacetime to "explain" the Newton's gravitational law. It isn't the explanation the way you had written.

    In physics, there isn't really a "why". It is mainly a "how". We can explain things by using something more fundamental, but if you look at it closely, at the origin of it, is more of a description, rather than an "explanation" of the why. You were told by cephid of this.

    Zz.
     
  12. jtbell

    Staff: Mentor

  13. Ι will disagree my dear. I think that in science we do not need only the "how",but the "why" too.
    That is because with "how" we learn the way that something happens.
    But with the "why" we learn why this way there is. So the "why" is stronger,because if you know the "why" you know and the "how",but not the opposite.
     
  14. cepheid

    cepheid 5,194
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    Just to add to what ZapperZ said: we weren't originally talking about gravity as described by General Relativity (GR). We were talking about classical (Newtonian) gravity. GR is a newer theory that supersedes Newtonian gravity, in the sense that is has been shown to be more "correct" (it applies over a wider range of circumstances and explains observed phenomena better). But as far as Newton, all he said was that the gravitational force between two masses is proportional to the product of their masses and inversely proportional to the square of the distance between them. He readily *acknowledged* that he had no idea HOW two masses could exert a force on each other over a great distance, without contact. In other words, his theory only explained how gravity *worked*, not what it WAS (in terms of a causal mechanism). GR is slightly better in the sense that it explains gravitation in terms of the curvature of spacetime, but as Zz pointed out, one could then very well ask why mass curves spacetime. Science seeks to describe nature and explain its behaviour in terms of physical laws, but when you keep asking "why" questions, you eventually reach the point where your theory has no answer other than "because that's the way nature is." Asking WHY nature is the way it is, is arguably more of a philosophical question. Science just answers the how and the what. What is nature like? How does it work? NOT why does it work the way it does?
     
  15. cepheid

    cepheid 5,194
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    There are at least two different kinds of "why" questions. The first (which science can answer) are actually "how" questions in disguise. When you ask, "Why does this phenomenon work the way it does?" you are actually asking what the causal mechanism for it is, in terms of more fundamental things. E.g. explaining a macroscopic observed phenomenon in terms of the behaviour of fundamental subatomic particles. But the second kind of "why" questions asks for a purpose or intent, rather than just an explanation. There is none. Once you reach your fundamental objects (like subatomic particles) you get to questions like, "why are there x number of fundamental particles, and not x+1, or x-3?" Why do these particles have the masses they do, instead of some other mass? As of yet, there is no answer for these questions, and there may never be, unless if we come up with a more fundamental theory that explains subatomic particles in terms of some other underlying phenomonon (like a bunch of tiny vibrating strings). But then you would ask WHY the strings have the properties that they do, and again there would be no answer, other than, "because that's what we observe. That's how nature seems to work."
     
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  16. This is simply wrong. Many priests will tell you exactly "why" with no clue "how". There is no order or hierarchy of answers here, they are simply different types of answers and getting one may offer little or no insight to the other.
     
  17. Wow! Excellent answer.
     
  18. Guys I am just a child that wanna learn. Why the **** you are so bad??
    First scientist were philoshopher. I like ask "why" and I will continue do that. Also If someone can not answer the "why",that means that an other power works(God),and I believe to god for this reason too.
     
  19. ZapperZ

    ZapperZ 30,004
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    Because of your attitude. You came here, asking a question, and then you turned around and start to try and "educate" the rest of us. Think about it. Many of us here are practicing physicists. We are not amateurs. And yet, you are lecturing us as if you are an expert in physics, and how physics is done! Go back and look at what you've written. It's as if you think we are ignorant of General Relativity and the history of physics.

    If you really are a "child", then don't act as if you know what you've said.

    Then you already have made up your mind based on what you believe in. You are not here to learn, contrary to what you have said. You are here only to strengthened your beliefs.

    Zz.
     
  20. That is not true.Anyway that is your opinion and I respect that.
     
  21. Great! Then I hope you have learned from the excellent answers provided (especially cephids answer)
     
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