Gravity in One Dimension two point masses, ml and m2, lie on the x-axis, with m, held in place at the origin and m, at position x and free to move. The gravitational potential energy of these masses is found to be Vex) = -Gm1 m2/x. where G is a constant (called the gravitational constant). You'll earn more about gravitation in Chapter 12 Find the x-component of the force acting on m, due to m1. Is this force attractive or repulsive? How do you know?