a. Besides his work on universal gravitation (gravity),Newton developed the three laws of motion which form the basic principles of modern physics. His discovery of calculus led the way to more powerful methods of solving mathematical problems.
b. If it was the same force, then a connection would exist between the way objects fell and the motion of the Moon around Earth, that is, its distance and orbital period. ... Newton went further and proposed that gravity was a "universal" force, and that the Sun's gravity was what held planets in their orbits
