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Dynamics and theory

  1. Oct 26, 2011 #1
    I'm back again, this time regarding questions relating to Newton's laws of motion. :)

    1. The problem statement, all variables and given/known data
    Imagine an astronaut in space at the midpoint between two stars of equal mass. If all other objects are infinitely far away, how much does the astronaut weigh? Explain your answer.

    3. The attempt at a solution
    I'm not sure how to answer this, my initial thought was weightless, because equal forces of gravity are acting in opposite directions.
  2. jcsd
  3. Oct 27, 2011 #2

    Filip Larsen

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    Gold Member

    He would be weightless, yes, but not for the reason you mention.

    If you think about weight of an object as how much force is applied to the surface of this object (i.e. how much force an astronaut feels on his feet when standing), then under what circumstances would there always be weightlessness? Would an astronaut in orbit around a single star be weightless despite that he is accelerated by gravity?
    Last edited: Oct 27, 2011
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