Machian Effects Inside a Rotating Spherical Shell

During typical general relativity courses, the gravitational fields generated by rotating objects and the so-called frame dragging effect are explained by emphasizing the presence of a gravitational Coriolis-like force term. It is well known that, in a rotating system, there is also a fictitious centrifugal force. In general, textbooks do not discuss also the possibility of a gravitational centrifugal-like force, and, in a recent paper, we have analyzed the presence of a repulsive force in the vicinity of a rotating mass. Now, however, we want to reviews some historical aspects of Mach’s Principle and to analyze the centrifugal gravitational term inside a rotating spherical shell, with a new simple approach.