Why at equator the speed of earths rotation is maximum?
The quick and dirty: Because the points along the equator are the earth’s surface points, generally speaking, that are farthest from the axis of rotation. It is similar to this idea. Imagine that you are spinning a bicycle wheel on its axle. Points along the tire surface are moving more rapidly than points on a spoke very close to the axle. The points on the tire are covering a longer distance over the same period of time.
