Serway & Jewett — Universal Gravitation: Problem 29

Let \(\Delta g_M\) represent the difference in the gravitational fields produced by the Moon at the points on the Earth’s surface nearest to and farthest from the Moon. Find the fraction \(\Delta g_M/g\), where \(g\) is the Earth’s gravitational field. (This difference is responsible for the occurrence of the lunar tides on the Earth.)