* newton's laws and the motion of satellites
the motion of the planets around the sun can be described by the equation r^3/T^2 = GM/4 pi^2. this equation is found by comparing the force from the law of universal gravitation with the force required to keep an object in circular motion. it represents the mathematical form of kepler's third law.
kepler's laws not only apply to planets and comets orbiting the sun, but they also apply to satellites (natural and artificial) and spacecraft orbiting planets. kepler's third law can, for example, be used to calculate the mass of a planet by determining the period and radius of a satellite of that planet.
newton's law of universal gravitation determines the motion of satellites, enabling scientists to calculate their position and velocity at any instant. it also controls the motion of spacecraft travelling through the solar system to other planets.
that's all i've got, sorry