Eli5: how does centrifugal force simulate gravity?

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I read a lot of sci-fi, and simulated gravity is a frequent feature of space sci-fi. I am interested in real physics, not hand-wavy magic artificial gravity. In the Expanse, highly efficient nuclear rockets create the experience of gravity by way of constant acceleration. This is easy for me to understand – on the vessel, the deck you are standing on is accelerating and pushing against your feet.

What I do not under is how centrifugal force acts in a way similar to gravity. I have a scenario in my imagination that illustrates my confusion. I imagine that a torus-shaped station in space has stopped rotating and everyone evacuated. A repair person in a space suit has floated into the station to repair it. He or she travels in microgravity in a space between the inner walls and outer walls of the station, almost like someone floating inside of a holo donut. While inside the immobile torus, and suspended between the walls in such a way that he or she isn’t touching either the innermost or outermost walls of the donut, s/he completes the repair needed to spin up the station again.

What happens next? The sci-fi I have read would lead me to believe that as the torus begins to spin up, the repair person will experience an effect similar to gravity and will coast toward the outermost wall until the inside of that wall becomes like a floor to them. If that is true, why? I would think that a person suspended within the boundaries of a torus would continue to float while the innermost and outermost walls in front of and behind them spun in their cycle. I don’t get why this spinning will make the repair person drift to one side and create a “down” to their perspective. Can anyone enlighten me?

Tl;dr: centrifugal force confuses me, and I don’t know why it works in microgravity(or just fundamentally misunderstand it)

In: Physics

6 Answers

Anonymous 0 Comments

Your thinking is correct. They would initially just float there. The air would be touching the walls though and would probably reach some kind of equilibrium with the walls (like when you stir a pot of water or some liquid with bubbles and particulates on top and after you remove the spoon it looks like the surface is rotating as a disc). That moving air is going to then blow around with it.

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