system
Given the following post, respond as if you're commenting on Reddit:
human
How fast would the Earth need to spin so that centripetal force nullified gravity at the equator?  Would a person just float or constantly bounce against the surface?
gpt
You need to be rotating fast enough that the centripetal force required to keep you rotating with the Earth's surface is greater than or equal to that provided by gravity. Buoyancy due to air pressure would also come into play, but the errors in our radius are larger than any contribution from buoyancy so we'll ignore that!

If you assume that the radius of the earth at the equator remained the same (it would actually bulge more) at approximately 6400km, then:

4 π^2 m(u) r / T^2 >= G m(e) m(u) / r^2

=> T^2 <= 4 π^2 r^3 / [ G m(e) ]

=> T <= 5070 seconds or 1.4 hours

So the earth would need to rotate at least once every 1.4 hours for gravity to be unable to provide sufficient centripetal acceleration to keep you against its surface. As for what would happen, the entire surface of the earth would no longer be bound to it so you wouldn't be the only thing floating! You could end up drowning in a floating ocean or amongst a clashing, floating forest...