21. :: : : It's only a mathematical impossibility in the 2-body point mass ( or rigid ball ) model. 22. Planetary motions in the Solar System can be computed with sufficient precision if they are treated as point masses . 23. It's true that the Earth is sometimes modelled as a point mass with all the mass at the center. 24. Can I use the continuum hypothesis, or can a body be considered rigid, or even as a point mass ? 25. Kepler's Laws are a strict mathematical consequence of Newton's Law of Gravitation when one has only two point masses . 26. In orbital mechanics, the equations of motion of planets are formulated as point masses located at the centers of mass. 27. Similar behavior is observed for a double pendulum composed of two point masses rather than two rods with distributed mass. 28. The expression gives the gravitational potential associated to a point mass or the Coulomb potential associated to a point charge. 29. In order to complete the equations of motion, the acceleration of the point mass attached to the pendulum must be computed. 30. The solution for a two-body problem is the Kepler orbit; spheres can be treated as point masses located at their centers.
