<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Newton's law of universal gravitation states that every particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers . This is a general physical law derived from empirical observations by what Isaac Newton called inductive reasoning . It is a part of classical mechanics and was formulated in Newton's work Philosophiæ Naturalis Principia Mathematica ("the Principia"), first published on 5 July 1686 . When Newton's book was presented in 1686 to the Royal Society, Robert Hooke made a claim that Newton had obtained the inverse square law from him . </P> <P> In today's language, the law states that every point mass attracts every other point mass by a force acting along the line intersecting the two points . The force is proportional to the product of the two masses, and inversely proportional to the square of the distance between them . </P>

Who wrote the equation for the law of gravitation