The Moon passes the sun at a speed of 1+ km/s ~ 2300 mph. The Earth rotates at 1000 mph at the surface, the moon orbits the same direction as Earth spins, so the effective shadow speed across the surface is less and varies with each eclipse, but always more than 1000 mph.

Note the Moon orbiting the same direction as Earth spins, meaning the shadow will move from west to east.


So. That's my high school dropout explanation, anyways