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

If you aren’t touching the walls in a vaccuum and are stationary, the revolving reference frame doesn’t affect you. You’ll just sit there with the wall spinning near you. But as you start to come up to speed (either because the air is also spinning and taking you with it, or because you’ve touched the wall and are being dragged with it), then your body will try to continue moving in a straight line and be frustrated by the wall of the torus, which will result in a pseudo-force that appears (to you) similar to gravity. Once you’re up to speed, you can walk and jump around normally.

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