Applied Physics and Mathematics Annotation << Back ON AN UNAVOIDABLE RELATIVISTIC PARADOX V.A. LEUS Several contradictions inherent in relativistic dynamics get evident in the case of mechanical systems of cyclic action. In the present paper a version of situation taking place in the moving belt transmission is examined. It is shown that non-Euclidean internal geometry, appearing during acceleration, does not abolish the real paradox in this mechanism. Keywords: special relativity theory, general relativity theory, Bell-effect, cyclical mechanism, unavoidable paradox. DOI: 10.25791/pfim.01.2022.1218 Pp. 03-05.