1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Gravitational Field and free fall

  1. Aug 9, 2015 #1
    The acceleration of free fall at the equator is not equal to the acceleration of free fall at the poles.explain?
     
    Last edited by a moderator: Aug 9, 2015
  2. jcsd
  3. Aug 9, 2015 #2
    The main reason is centifugal force of spinning of earth. Besides, earth is not a perfect spheroid, it is a little flattened because of this centrifugal force.
     
    Last edited: Aug 9, 2015
  4. Aug 9, 2015 #3

    faiziqb12

    User Avatar
    Gold Member

    i dont know what centrifugal force has to do with gravitation
    gravitation is just a matter of distance and mass
     
  5. Aug 9, 2015 #4

    A.T.

    User Avatar
    Science Advisor
    Gold Member

  6. Aug 9, 2015 #5

    faiziqb12

    User Avatar
    Gold Member

  7. Aug 9, 2015 #6

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    The original post did not ask directly about "gravity", it asked about "the acceleration of free fall". That has to do both with gravitational force and with "centrifugal force" (actually the fact that part of that gravity goes to supply centripetal force keeping the object from flying off the rotating earth).
     
  8. Aug 9, 2015 #7
    If you are on surface on equator, I think that this is clear. Centrifugal force pushes you up. But if you are above the surface of equator and you are falling toward earth, you are also moving in the direction of rotation, but this means, that you are falling slower in comparison to nonrotating earth or on poles.
     
    Last edited: Aug 9, 2015
  9. Aug 9, 2015 #8

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    That's what this thread is about.
     
  10. Aug 9, 2015 #9
    But it is interesting if some meteoroid falls toward earth on equator. It falls like toward non-rotation earth, thus it does not feel earth's centrifugal force.

    Maybe this is what annoying you.
     
    Last edited: Aug 9, 2015
  11. Aug 9, 2015 #10

    faiziqb12

    User Avatar
    Gold Member

    maybe centrifugal force effects gravitation on land and not in the sky
     
  12. Aug 9, 2015 #11
    This is not precisely. If you throw a stone from equator, its acceleration is smaller because of centrifugal force. Because rotation of earth is in-calculated in it.
     
  13. Aug 9, 2015 #12

    faiziqb12

    User Avatar
    Gold Member

    i said maybe
     
  14. Aug 9, 2015 #13
    Thus, centrifugal force causes also on stone in the air (which flies from earth), but not on stone which flies from the universe.
     
  15. Aug 9, 2015 #14

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    Centrifugal force exist only in the rotating reference frame of the Earth, no matter if on land or in the sky. In the inertial frame there is no centrifugal force, no matter if on land or in the sky.

    https://en.wikipedia.org/wiki/Centrifugal_force
     
  16. Aug 9, 2015 #15

    faiziqb12

    User Avatar
    Gold Member

  17. Aug 9, 2015 #16
    How do you explain that the gravitational acceleration is increased at the poles (compared to non rotating body) even though there is no centrifugal force?
     
  18. Aug 9, 2015 #17
    This looks a lot like an end of chapter question.
    It should be in homework section, shouldn't?
     
  19. Aug 9, 2015 #18

    faiziqb12

    User Avatar
    Gold Member

    the gravitational force isnt affected at the poles by the centrifugal force{which is opposite in direction of gravitational force}...............
    so at the poles the gravitation is somewhat the same as it should be...
    but near the equator the centriful force plays its part so the gravitation gets decreased a little....
     
  20. Aug 10, 2015 #19

    A.T.

    User Avatar
    Science Advisor
    Gold Member

    It's only opposite in direction exactly at the equator, not on the rest of the Earth. At the poles it's zero, so it's not opposite to anything.
     
  21. Aug 10, 2015 #20
    It is not the same as it would be without rotation.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Gravitational Field and free fall
  1. Free falls (Replies: 2)

  2. Free fall (Replies: 10)

  3. Free Fall (Replies: 2)

Loading...