# When I move my arm forward in vacuum, will my body move backward?

Let's say I stay at point $x=0$ in vacuum. When I move my arm forward such that it will have a positive $x$ position (say $x=5$) will the rest of my body move backward such that it will have a negative $x$ position (like $x=-1$)?

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hmm, lets say one can lift oneself up by pulling the straps of one's shoes? –  Nikos M. Aug 9 at 22:31