The acceleration needed to make a turn with radius r at speed v is. v²/r (https://courses.lumenlearning.com/suny-physics/chapter/6-2-centripetal-acceleration/ h

The acceleration needed to make a turn with radius r at speed v is. v²/r (https://courses.lumenlearning.com/suny-physics/chapter/6-2-centripetal-acceleration/ https://courses.lumenlearning.com/suny-physics/chapter/6-2-c...) If that combined that with earth’s gravity has to give you 1.1g, that has to be (via the Pythagorean theorem) about 0.2g or 2m/s². Let’s pick r = 100m. Then, v² has to be 20, giving as a velocity of about 16 km/hour. r = 1km would require about 50km/hour. Sounds doable, until you consider your “put gyms, hotels, swimming pool, living quarters, etc. in it”. That’s a lot of mass and space. Centrifuges that we put potential astronauts and fighter pilots in are a lot smaller. On the other hand, there’s the idea of “a massive floating railway, Maglev-style, which will travel along a track with a radius of 2.5 kilometers within an underground vacuum tunnel. The machine will run on excess energy generated from wind and solar, and it can reach speeds up to 2,000 km/h. When the renewable energy production is insufficient, the kinetic energy from the train movement will be reconverted and sent to the grid.” that engineers claim can be built (https://www.greenoptimistic.com/energy-train-mph/ https://www.greenoptimistic.com/energy-train-mph/). That would hit over 10g and weigh a lot more than that hotel. I can’t find updates, though.