We are most familiar with gravity close up. How does local, near-Earth gravity relate to what you’ve learned so far? In this section, we establish the connection between Newton’s universal law of gravitation and the formula F = mg that we previously used for gravity. This will lead us to clarify the significance of the acceleration due to gravity g. We’ll then discuss how g varies with distance from the center of the Earth, and how it differs on other celestial bodies.
The force of gravity near the Earth’s surface
Time to come back to Earth! At the beginning of this chapter (as well as in previous chapters), we said that the force of gravity near the Earth on an object of mass m is given by F = mg, with g being approximately 9.81 ...