Law of Gravitation
Newton's Law of Gravitation states that any two objects in the universe attract each other with a gravitational force that is proportional to the product of their masses and inversely proporional to the square of the distance separating their centers. The direction of the force is along the line joining their centers. If two objects of masses m1 and m2 are separated by a distance r, then
Fg = Gm1m2 ⁄ r 2
Fg is the gravitational force exerted by one on the other. G is a universal constant called universal gravitational constant. Its value is 6.67 * 10 -11 N m 2 ⁄ kg 2.
G = 6.67 * 10 -11 N m 2 ⁄ kg 2
The force exerted by m1 on m2 and by m2 on m1 are action reaction forces. They have equal magnitude but opposite direction.
Problems Involving Circular Motion
The following are examples involving circular motion.