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Weightlessness due to gravitational field

  1. Aug 18, 2008 #1
    Astronauts in a space capsule orbiting the earth at a height of 900km experience weightlessness: hence the gravitational field due to the earth must be zero at that altitude'.

    Can someone please help ?
    What does it mean?
  2. jcsd
  3. Aug 18, 2008 #2


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    Homework Helper

    Someone posted that gravity at the space station is about 90% as strong as it is at sea level. The astronauts are in free fall, but moving fast enough perpendicually to the force of gravity that the inwards acceleration from gravity results in their path being an orbit around the earth at a near constant speed and distance.
  4. Aug 18, 2008 #3
    i still dont get it.. please explain clearly
  5. Aug 18, 2008 #4

    Doc Al

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    Read this: [Broken]
    Last edited by a moderator: May 3, 2017
  6. Aug 19, 2008 #5
    They're still experiencing gravity in an inverse square relation to their distance from the Earth's center.
    However, so is their space capsule....

    They're both free-falling back to the earth with a tangential velocity that prevents them from ever actually reaching the earth.
  7. Aug 19, 2008 #6
    In a nutshell: Force of gravity = Centrifugal Force from spinning around the earth
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