Three balls, with masses of 4m, 2m, and m, are equally spaced along a line. The spacing between neighboring balls is r. We can arrange the balls in three different ways, as shown in the figure. In each case, the balls are in an isolated region of space very far from anything else. Rank the three cases, from largest to smallest, based on the magnitude of the net gravitational force experienced by the ball with the mass of 4m, because of the other two balls