In this article the resolution of the famous Ehrenfest paradox [1] is presented. The paradox relates to a spinning disk and the Special Relativity Theory (SRT) applied to it. The paradox resolution is based on the proposition that the paradox results from an incorrect application of SRT to a system that is not in an inertial motion. The centrifugal and centripetal forces resulting from the rotation are always present and need to be accounted for. Using the author's previously derived metric for the axially symmetric space-time the effect of centrifugal and centripetal forces can be correctly included. When this is done no paradox is obtained and it is shown that the spinning disk appears to have flat space-time geometry. This finding also provides the correct interpretation of the null result of Michelson-Morley experiment, the correct explanation of the Fizeau experiments, and a simple and consistent explanation of the Sagnac effect. The theoretical descriptions of all these experiments should, therefore, always include the effect of the centrifugal force of Earth's rotation. The measured data from other experiments conducted on rotating systems are explained by the inertial mass increase as correctly described by SRT.