If the earth suddenly starting spinning faster (or even stopped) what would happen?

Everyone and thing would find themselves sliding, instantaneously at least, in a great circle that would be tangent to their original latitude circle and the same latitude in the opposite hemisphere, and with the same linear speed equal to (roughly) 25k mi/day times the cosine of their original latitude (0 = equator, 90=pole). That leaves a linear speed of 0 for anyone at the poles, and they would rotate in place with a frequency of (1/86400) Hz. (i.e.

1 day^-1). The path as viewed from the even more accelerated earth frame is much screwier, due to the axial tilt of 23 degrees or so between the Earth's polar axis and the axis of its orbit about the Sun. Come to think of it, this will pull the polar spinners out of their lonesome spots.

Everyone, it seems, would get to visit both hemispheres. Eventually. Barring collisions.

Edit: Ben: Yes, any two individuals paths will cross at antipodal points, but that doesn't mean those two will collide. For a collision, they both have to be at the same point at the same time, If A and B are at the same longitude, equidistant from the equator, they will remain equidistant as they slide, and will indeed collide at their next equator crossing. Normally, though, when you cross someone else's path, they will be somewhere else on it at the time.

That brings up another cute setup. (All ignoring the effects of orbiting the Sun with a tilted axis.) Any group of persons equally spaced around a given latitude circle, will remain equally spaced in a circle at all times, and that circle is concentric with the equator. (Speaking "spherically", that is.

The common center is the N or S pole.) The reason for great circles is that that's the straightest path possible. The only forces on a body on a perfectly spherical frictionless Earth would be the downward force of gravity and the upward reaction force of the Earth's surface. Both of these are in a line between the body and the Earth's center, so the Earth's center is the center of the body's motion.

(This time, I mean the center of the circle in it's plane.).

The interesting part of this problem isn't the fact that the earth has suddenly stopped, it's that the earth is a frictionless perfect sphere. The inhabitants of that earth would have no way to tell if it were rotating or not if it were frictionless. As already shown, nobody would fly off into space.

If that were a problem, it would be a problem even on the normal, frictional earth. The one additional interesting thing that would happen would be that now the Coriolis effect would be a part of every day life. I haven't thought about it in a while, but I think that the main effect would be that people would tend to rotate in place about once a day (once a day at the poles, zero rotation at the equator, and different rotation rates inbetween), but there should also be a gradual drift towards the equator (pretty small, but hey, it's frictionless).

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.