Two masses are attracted by a gravitational force of 9.4 N. What will the force of attraction be if the distance between the two masses is quadrupled? Newton's Law of Gravitation The gravitational force between two objects is proportional to the mass of each object and inversely proportional to the square of the distance between the centers of the masses: F _ Grills!2 _ 2 , r where G is a constant. The direction of the force is attractive and lies along the line joining the centers of the two masses (fig_ 5.19) m' m} Fr . gure 5.19 The gravitational force is attractive and acts along the line joining the center of the two masses. It obeys Newton's third law of motion (F 2 = - Fl). The force of attraction will be S N