College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

Exercise 27

In the cases of both stable and unstable equilibrium, a small displacement of the center of gravity causes gravitational work to be done. (See the balls and bowls in Fig. 8.11.) However, there is another type of equilibrium in which the displacement of the center of mass involves no gravitational work and the displaced center of gravity essentially moves in a straight line. This is called neutral equilibrium. Give an example of an object in neutral equilibrium.