This document discusses Newton's law of universal gravitation and provides examples of calculating gravitational force. It begins by defining gravitational force as a mutual attraction between particles of matter that exists regardless of the medium or masses involved. It then provides Newton's equation for gravitational force as being dependent on the masses of the objects and the distance between them. Examples are given of calculating gravitational force and distance between objects based on their masses and the measured force. Homework questions at the end involve calculating escape velocity from Earth and questions about black holes.