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? Earth's Gravitational Field

  1. Aug 29, 2005 #1
    ???? Earth's Gravitational Field

    Hi, i have a physics question in my physics portfolio, it goes as follows

    Critically assess the following statement: ‘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'. Include calculations in your answer.

    Can someone please help ?
     
  2. jcsd
  3. Aug 29, 2005 #2

    russ_watters

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    Have you tried the calculation?
     
  4. Aug 29, 2005 #3
    i dont know what to calculate
     
  5. Aug 29, 2005 #4

    ZapperZ

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    Think about this for a minute. If you are moving in a circular motion (which we will approximate the orbit to be), is there any acceleration on the capsule+astronauts system? If there is, there's a net force applied to that system. If there's no net force or acceleration, you'd have Newton's First Law. Is that what you have in this situation?

    Once you figure that out, THEN you can start to try to explain why the astronauts experience weightlessness, which will lead to the conclusion that "weightlessness" does not mean zero gravitational force (example: astronauts training in the "vomit" plane).

    Zz.
     
  6. Aug 29, 2005 #5

    ZapperZ

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    I just realized that you posted this in more than one location. Please do not do that! Spend some time reading our Guidelines before posting.

    This thread is closed.

    Zz.
     
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