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Acceleration and Gravity

  1. Jun 26, 2014 #1
    What is the difference between acceleration and gravity?
    Are they same?
  2. jcsd
  3. Jun 26, 2014 #2

    Simon Bridge

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    Depends who you ask.

    According to Newton, gravity is a force that gives rise to acceleration.

    Einstein points out that you cannot, locally, distinguish uniform acceleration from gravity.

    Certainly you can have acceleration without gravity - so, while gravity may thought of as an acceleration, not all accelerations are gravity.

    Are you are thinking of spinning a space station to simulate gravity?
    That is different from gravity.
  4. Jun 26, 2014 #3
    What kind of acceleration is different from Gravitation?
  5. Jun 26, 2014 #4

    Simon Bridge

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    Any acceleration that is not gravity of course.
    The acceleration of a car on a level road is not gravity.
    The acceleration from spinning in a circle is not gravity.
    What is your education level?
  6. Jun 26, 2014 #5


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  7. Jul 3, 2014 #6
    So can anyone briefly explain me whats the equivalence Principle?
  8. Jul 3, 2014 #7
    How is gravity different with acceleration, if both produce the same effect?
  9. Jul 3, 2014 #8


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  10. Jul 3, 2014 #9
    Please provide an elaborated answer without reffering to wikipedia
  11. Jul 3, 2014 #10


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    If you are in a small room sitting on the surface of a planet, you notice that if you drop an object, it falls to the floor with a characteristic acceleration. This characteristic acceleration is the same for all objects--whether it's made of steel or plastic or whatever. (This is only literally true if you ignore wind resistance, of course.)

    If instead of a room sitting on a planet, you're in a room on board an accelerating rocket, you notice exactly the same behavior in dropped objects.

    Now, there really is a detectable difference if you perform very careful measurements. Gravity on the surface of a planet decreases as you get farther from the center of the planet according to the inverse-square law (if you are twice as far from the center, the gravity is 1/4 as strong). The fake gravity on board an accelerating rocket doesn't have that kind of drop-off.

    Roughly speaking, the equivalence principle says that the ONLY difference between these two cases (on a planet vs. on an accelerating rocket) is the variation of the acceleration with location. So to the extent that your room is small enough that you can't detect differences in gravity within the room, you won't find any differences between the two cases.
  12. Jul 3, 2014 #11


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    Please do some of your own study .... we are not going to spoonfeed you

    if you find specific things in your reading of the subject, then ask specific questions :smile:

  13. Jul 3, 2014 #12
    That's quite an effort you ask of us. You know we are all unpaid volunteers right? Why would we make such an effort for you if you can't make the effort of reading wikipedia or other sources?

    You have asked in this thread many basic questions that you could probably have found yourself if you searched for a while.

    The idea of this forum is that we will help you provided that you do your own searching first. So read wiki, read other sources. Then ask us about what's confusing you or what you don't understand.

    Please read this: https://www.physicsforums.com/blog.php?b=3588 [Broken]

    Thread locked.
    Last edited by a moderator: May 6, 2017
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