The paper aims at the kinetics of a body under free fall, especially free body motion, the motion occurring in the Earth environs space, that is in the range of the gravity action. A new adequate theory of such a motion, opening new not known kinetic magnitudes, has been elaborated. This theory has its source, which is the dependence of the way length on time. That is the way characteristics created in this work. The worked out theory has been verified by experiment, referred to two different realities. One of them was the body motion in the air environment of the Earth environs space, with the second one occurring in a determined machining space-time. The adequate earth acceleration/gravity has been calculated taking advantage of the theory elaborated; and its value, as indicated, is equal 3.85 mźs-2. Two kinds of accelerations have been separated: inertial and gravitational. The relations occurring between their values on the neighbouring potential fields, unstable, and stable, have been discovered. That discovery indicates on the existence of quantum nature of gravitation.