WESSONS GRAVITY AND MACHS PRINCIPLE

The general expressions of the variation of the rest mass of a test body with proper time and spatial position in a gravitational field are given in the framework of Wesson's 5D space-time-mass gravity. The position-dependent variation of the rest mass of a test body in a quasi-static and spherically symmetric gravitational field is discussed, and it is indicated that such variation embodies the spirit of Mach's principle in the sense that the inertial mass depends on the distribution of matter in the universe. © 1990.