I read that since the earth vid rotating on its axis ,an object on the earth surface experiences a centrifugal force because the object is also moving around the earth's axis.So,that centrifugal force causes gravitational acceleration to lessen and we write •F=Gravitational force-the horizontal component of centrifugal force . But if the object is rotating it should experience a centripetal force as well.Then why wasn't it included in the above calculation ? Or is it that I have got things wrong? MOREOVER,I read that an object moving round the earth would experience the same amount of centripetal force and centrifugal force .What happens to gravitational force .are they 3 related somehow.Why is it not the same for an object at rest on the earth's surface ? Please help.I couldn't help myself understand those things neither with the help of books nor the internet.