The Relative Inertiality - The Relative Mechanical Movement of Bodies in Outer Space

Abstract

Even though classical mechanics states that it is not possible to find an inertial reference frame, relative measurements are used to determine the mechanical behaviour of celestial bodies with very small dimensions compared to the distances between them. The present work aims to demonstrate that the two fundamental theorems of mechanics, the momentum theorem and the angular momentum theorem, remain valid if we use the relative distances and velocities between these celestial bodies. The starting point for developing such a result is that the basic assumptions of Newtonian mechanics are considered to be valid and are used with the assumption that an inertial reference frame can exist, even if only hypothetically. Relationships are established between the relative accelerations and the global forces acting on each body in a two-body ensemble, which are quite similar to those stated in an inertial reference frame.

Keywords

• inertial reference frames
• relative mechanical motion
• general equation of relative motion