Two point masses m are held in place a distance d apart. Another point mass M is midway between them. M is then displaced a small distance x perpendicular to the line connecting the two fixed masses and released. (i) Show that the magnitude of the net gravitational force on M due to the fixed masses is given approximately by Fnet ≈ 16GmMx d 3 if x d. What is the direction of this force? Is it a restoring force?