Numerical analysis of a planar motion; GeoGebra as a tool of investigation

Abstract

The paper is inspired by the method of the numerical approximation of the planetary motion that was used by Richard Feynman in the book  The Feynman Lectures on Physics.  Using Newton's Second Law and replacing infinitesimally small changes in variables by their very small changes, he arrived at a respectable approximation of the elliptical motion of a planet around the sun. To organize all numerically computed data, which include the sequence of coordinates of the consecutive positions of the planet during its motion around the sun, Richard Feynman used a large table. Then, the plot of the resulting successive positions of the planet was in accordance with Kepler's laws. We show that GeoGebra, which enables a user to combine the spreadsheet with the numerical and graphical tools, is very suitable for grasping such complex tasks based on repetitive numerical computation and graphical planar representation.