Welcome to The Cave of Dragonflies forums, where the smallest bugs live alongside the strongest dragons.
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Of course I'm not forcing you to do anything if you don't want to, but seriously, what have you got to lose? Five seconds of your life?
Speaking of xkcd, I actually had a physics test once where one of the questions involved this strip, and you were supposed to estimate the actual amount of time by which dawn would be delayed with each spin.
It was ages ago so I don't remember the specifics, but they probably provided the information necessary to make a reasonable guess. They weren't looking for accuracy anyway, it was sort of a Fermi estimate kind of thing.wouldn't that be a bit difficult without knowing either the exact moment of inertia of the earth or its mass distribution, where neither is simple to measure to significant significance?