A body moving in a circular path experiences centrifugal force. A body at rest does NOT. There are so many other 'school-boy howlers' in just this page of this site, that it would keep me busy for days just lightly addressing them. Paul D Paul D "A body at rest does NOT." Here we go again Paul.. Your statement is not thought out.. A body in a state of rest relative to what? Nobody knows or can prove any point to be in a "state of rest" or movement relative to the universe. The base line cannot be determined. That there is observable rotation between the earth and its GS, with relation to the star system is true . Proving which is moving cannot be shown . You make the "assumption" it is the earth system rotating, but can offer no certain proof. We state the certainty because its Gods word, that the Earth is static, but can offer no proof of which is moving. But there is proof of the existence of God, for those who do not refuse to seek it. We are left then, with two faiths. One based on certainty, and one based on theoretical assumptions. If those who base their science on certainty are right, then your assumptions are wrong, and another reason for the force has to be found.. I leave with one thoughtful question. Which philosophy is most likely to arrive at truth in science, that which excludes no possibility, or that which is exclusive and allows no metaphysics in to its equations, and with Voltaire declares dogmatically, 'There is no God' ? Philip.