Sir Isaac Newton developed calculus, natural forces and optics. Newton was born on Christmas Day 1642. His father had died before he was born, but he was still given his father's name (Westfall 17). Isaac stayed with his grandparents when his mother went to live with her second husband. While living with his grandparents, he attended the nearby day school (Westfall 17). After his grandmother died and Newton turned seventeen, his mother took him out of school and brought him back to the family farm. She tried to teach him how to run the farm and manage the estate; it was a failure. In all his free time, he devotes himself to inventing and building machines. Newton's uncle and old schoolmaster realized that he was in the wrong profession and urged his mother to prepare him to attend college. His uncle's efforts bore fruit; in 1660 he returned to Grantham to complete his secondary education and prepare for university. In June 1661, Newton entered Trinity College, Cambridge (Westfall 17). At Cambridge, Newton studied mathematics. It was at this time that Newton began to make many discoveries. He made most of his important discoveries there: pure mathematics, the theory of gravitation and optics, even before graduating from college. Newton made contributions to all branches of mathematics. The modern study of aerodynamics and the science of hydrodynamics would be impossible without the principles of calculus. Newton wrote Philosophiae Principia Mathematica (Mathematical Principles of Natural Philosophy), generally known by the last two words. "In the book, Newton codified Galileo's discoveries according to the three laws of motion." (Wilson online). Newton formulated three laws of motion, resulting in the law of universal gravitation. Its laws of motion are the natural laws of mechanics. Newton's three laws of motion are: 1. The law of inertia: An object at rest tends to remain at rest unless acted upon by an external force. 2. 2nd law – an unbalanced force applied to an object will cause the object to accelerate. There was an equation that accompanied this law which is F=ma.