There are two main cases, one for rotation (A) and one for translational motion (B). (A) The Main Case for rotational motion deals with a simple yet practically and historically important example of a mechanical systemthe clock balance wheel. It's perfection by John Harrison (1693 1776) made it possible to keep accurate time on ships. (B) The Main Case in for translational motion calls for the modeling of the motion of bodies in the solar system near so-called Lagrange points. The Sun and a planet (such as Jupiter or Earth) for a system where some special points possess certain interesting stability properties. It has been suggested to park spacecraft at Lagrange points. | Main Cases |