why is side's move of earth from west to east?

Answer 1

Actually, if you think about it, these are just arbitrary directions. If you turned a desk globe upside down, then west is east, and east is west.

But why does the earth spin at all (or for that matter, why does it revolve around the sun)? In brief, the gravity of the dust and debris (as it all came together to form the planets) of the early pre-solar system set it all in motion.