A new variational principle for the fundamental equations of classical physics

In this paper we introduce a variational principle from which the fundamental equations of classical physics can be deduced this principle permits a sort of unification of the gravitational and the electromagnetic fields. The basic point of this variational principle is that file world-line of a material point is parameterized by a parameter a which carries some physical information, namely it is related to the rest mass and to the charge. In particular. the (inertial) rest mass will not be a property of a material point, but it will be a constant of the motion which is determined by the initial conditions. In this framework the equality between the inertial and gravitational mass can be deduced.