Can a person suspended in space with nothing to push off of, turn themselves around?
I think he can't if the space is empty and the weight is absent.
He can only produce internal forces which let him to extend the arms and to rotate the breast for example..
Every movement he makes can't accelerate him because it creates equal and opposite reaction forces
Yes, it's true: a cat rotates because it can produce two equal and opposite angular momentums, so the net angular momentum is zero.
Humans can do it too, for example by swinging the arms and legs around. In this video at 25:00min an astronaut does it in free fall:
http://www.physics.utoronto.ca/~phy189h1/Physics of Somersaults and Twists.pdf
Yes. If he gyrates his arms/legs in a clockwise direction, his torso will turn counterclockwise. Once he stops moving his limbs, he will be facing a new direction and no longer rotating.
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