By about 1665, Isaac Newton enunciated the principle of mechanics (Newton's laws of motion )formulated the law of universal gravitation, separated white light into colours, proposed a theory for the propagation of light and invented differential and integral calculus. Newton's contributions covered an enormous range of natural phenomena. He was thus able bodies follow a combination of his own second lae of motion and the law of gravitation, and to predict the appearance of comets, explain the effect of the moon in producing the tides, and explain the procession of the equinoxes. Subsequent development of physics owes much to Newton's law of motion , especially the second law which states that the force needed to accelerate an object will be proportional to its mass times the acceleration. His contribution to the description of forces led to the elucidation of the force of gravity- one of only four known fundamental forces in the universe, the others being: electromagnetic force, nuclear force and,the weak forces accounting for the phenomenon of radioactivity.
