  It is shown that gravitational nature of inertial mass (Mach principle)
agrees with idea of interaction of gravitational and electromagnetic forces and
does not contradict the laws of classical mechanics. According to the simple
phenomenological model the body inertial mass is directly proportional to its
gravitational mass and the sum of coefficients, which characterize degrees of
interaction of gravitational forces in accelerated motion of the body in
accompanying and opposite directions relative to the gravitational force.
