How does the speed of rotation affect the shape of the earth?

The rotation affects the shape of the earth because it causes the bulge at the equator and the flattening at the pole.

The earth has a spherical shape and this owes more to its internal composition.

Earth's mantle is fluid and made up of weak and ductile rocks. When the earth begins to rotate on its axis, the equator has more bulge and bursts outward than the rest of the part of the earth. This is why the rotation of earth affects its shape.