Description: After studying this lesson, you should be able to learn about, law of gravitation, value of acceleration due to gravity of a heavenly body, variation in the value of the acceleration due to gravity with height, depth and latitude, gravitaitonal potential and gravitational potential energy, force responsible for planetary motion, Kepler’s laws of planetary motion, orbital velocity, escape velocity, how an artificial satellite is launched, polar and equatorial satellites, conditions for a satellite to be a geostationary satellite, height of a geostationary satellite and their applications, achievements of India in the field of satellite technology