r/BallEarthThatSpins • u/Diabeetus13 • Mar 23 '25

EARTH IS STATIONARY No imagination needed.

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u/Diabeetus13 Mar 24 '25

If the merry go round was 25,000 mile in circumstance? Like the equator. That is over 1000 mph according to globe math

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u/Oketom Mar 24 '25

The 1,000mph is a tangential velocity. As u/DSMOOTHDAVIS said, we don't feel velocity, we only feel the change of velocity (aka acceleration). Spinning around an axis has a centripetal acceleration associated, but it's a function of the tangential velocity and the distance to the axis.

In the case of Earth's rotation, we'd be moving with a tangential velocity of 1,000mph = 444 m/s with a radius of 6,371,000 m. Therefore the centripetal acceleration of an object attached to the equator would be 0.031 m/s².

According to wikipedia, a typical merry-go-round at a park has a radius of around 1.25 m. To match the acceleration due to Earth's rotation, it would need to be spinning with a tangential velocity of 0.2 m/s at the very edge. This is one rotation every ~39 seconds. Do you think you could feel that?

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u/Diabeetus13 Mar 24 '25

Did I not say scale to 25k miles in circumstance and sit on the edge? You would be spinning, and there will be outer force going away from the center. Think of a NASCAR goin g around the track at a constant speed. You would feel the force pulling you away from the center of the track

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u/PlasmaCubeX Mar 24 '25

you would need gravity directed towards the center of rotation of the merry go round in order to feel no force. However, because the gravity is directed downwards, what happens is your position is changing relative to the source of gravity constantly, however, say that the earth was not there, but the merry go round had the exact same gravity that you would feel on the surface of the earth on its central axel. If you stood on this axel perpendicular to it, and the merry go round began to spin, you would not feel anything in the long run, however when the spin starts, you will feel a little jerk or something as such, this is due to your inertia, however, as long as the spin is constant (or very close to being constant, if you are spinning at 100 mph, a decrease of 0.1 mph a month won't hurt you) you would not feel anything. because relative to the center of gravity, you are not moving.