Six objects are placed at the vertices of a regular hexagon. The geometric center of the hexagon is at the origin with objects 1 and 4 on the x -axis (see figure). The mass of the k^ th object is m k=k M | q_ k | where i is an integer, M is a constant with dimension of mass, and q_ k is the angular position of the kth verted measured from the positive x -axis in the counter-clockwise sense. If the net gravitational f