The direction of Coulomb’s force and the direction of gravitational force in 4-dimensional space-time

In this paper, we point out that the 4-vector force exerted on a particle by another particle is always in the direction orthogonal to the 4-vector velocity of the exerted particle in 4-dimensional space-time, rather than along the line joining the couple of the particles. This inference is obviously supported from the fact that the magnitude of the 4-vector velocity is always a constant. This orthogonality brings out many new aspects for force concept. In this paper it is found that the Maxwell’s equations can be derived from classical Coulomb’s force and the orthogonality; some gravitational effects can also be explained in terms of the orthogonality between 4-vector gravitational force and 4-vector velocity, the results are the same as the general theory of relativity.