Newton's Law of Gravitation

Idea: Newton's Universal Law of Gravitation states that any two objects exert a gravitational force of attraction on each other. The direction of the force is along the line joing the objects (See Fig.(7.3)). The magnitude of the force is proportional to the product of the gravitational masses of the objects, and inversely proportional to the square of the distance between them. For the two objects in Figure 7.3:

Figure 7.3: Gravitational Force Between Two Masses


Definition: Gravitional Potential Energy

Due to the gravitational force of attraction, any two objects with masses tex2html_wrap_inline767 and tex2html_wrap_inline771 located a distance r apart have the ability to do work. Hence they have potential energy. The gravitational potential energy of such objects is: