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Random spacehsip question

  1. Aug 6, 2009 #1
    Hi, this is my 1st post so be gentle :smile:

    Just a random question... if you was in a spaceship that was 'stationary' and you had no means of propulsion, could u run and jump into the wall to make it move forwards or would the friction with the floor from ur movement cancel out the impact on the wall due to conservation of momentum or one of newtons laws.
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  3. Aug 6, 2009 #2


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    Every action has an equal and opposite reaction. ( Anonymous smart guy)

    If you run then you have to push the spaceship in the opposite direction to propel yourself forward. When you hit the spaceship wall you lose all energy and hence all motion same applies for the ships motion and energy.

    You will move the ship for a slit bit as you moved in a direction but the center of mass of you plus ship stays put.
    Last edited: Aug 6, 2009
  4. Aug 6, 2009 #3
    The most recent issue of Scientific American has an article on this. If the spaceship is in "flat" space, you are out of luck. But if the space the spaceship is in is (locally) curved by gravitation or has curvature due to the overall shape of space, then you can, by swimming motions, move yourself (and the spaceship).

    Read the article for more details.
  5. Aug 6, 2009 #4


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    Link to article please... very skeptical about articles.
  6. Aug 6, 2009 #5


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    The premise is that the space is is staionary, so gravitational effects aren't allowed.
  7. Aug 8, 2009 #6
    Every action has an equal and opposite reaction. Its not possible that you could run and jump into the walls to move the spaceship as you will first have to overcome the inertia of the spaceship.
  8. Aug 9, 2009 #7
    however to overcome the inertia of a space ship where there is virtually no other forces acting on it would require a very small force. if the spaceship moves through space it encounters a very small... if any resistive force therefore any force applied would be transformed into motion
  9. Aug 9, 2009 #8
    hmm inertia is dependant on the mass of an object so why would it requier a small force when there are no other forces acting on it???
  10. Aug 9, 2009 #9
    it is true, however if you did the same thing in an environment found on the earth there would be no change due to frictional forces etc acting on the spaceship. in space these forces are removed. Therefore what little impact to the spaceships velocity is achievable is maximised
  11. Aug 9, 2009 #10


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    Last edited by a moderator: Apr 24, 2017
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