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Suppose I am in the center of a hypothetical 4mx4m room and there is no gravity. I am wearing a spacesuit with no means of propulsion (e.g. venting, ejecting, etc..).

Would I be able to reach "the door", i.e. start movement in a certain direction, by body movements of some kind, or would I float in the center of the room forever?

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You cannot change the location of your center of mass without some form of propulsion. You can, however change your attitude by wiggling around like a falling cat.

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  • $\begingroup$ So is your answer "No"? Don't you want to find out if the room has an atmosphere first? Or do you think "swimming" is excluded by the "no means of propulsion? I can't really decide what it means. $\endgroup$ – uhoh Dec 13 '16 at 21:31
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    $\begingroup$ I would argue that "swimming" is some form of propulsion. Even if you admit the possibility, it would be remarkably ineffective, especially in a spacesuit that restricts mobility. $\endgroup$ – Tristan Dec 14 '16 at 16:01
  • $\begingroup$ Ya I think you are right about that. btw I really like that video clip! Here's an alternate video involving a rotating cat and a rocket scientist. $\endgroup$ – uhoh Dec 14 '16 at 16:13
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You haven't specified if you're in vacuum or not (though the spacesuit is suggestive).

If you're in vacuum, you're stuck, unless you started with some motion relative to the room, or something accelerates the room itself.

If you're in a fluid medium, even air, you can "swim", pushing the medium around you preferentially in one direction to accelerate yourself in the opposite direction. This would be slow going in air -- each stroke produces very little momentum -- but you could escape.

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  • $\begingroup$ That's a good point - the space suit is a not-so-subtle clue. However there are alternative explanations for the suit - my hypothetical ammonia leak or a prank. $\endgroup$ – uhoh Dec 14 '16 at 16:01

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