Sir Isaac Newton was a British physicist who, in many respects, can be viewed as the greatest physicist of all time. Though there were some predecessors of note, such as Archimedes, Copernicus, and Galileo, It was Newton who truly exemplified the method of scientific inquiry that would be adopted throughout the ages. For nearly a century, Aristotle's description of the physical universe had proven to be inadequate to describe the nature of movement. Newton tackled the problem and came up with three general rules about the movement of objects which have been dubbed by posterity Newton's three laws of motion.

In 1687 Newton introduced the three laws in his book Mathematical Principles of Natural Philosophy, which is generally referred to as the Principia, where he also introduced his theory of universal gravitation, thus laying down the entire foundation of classical mechanics in one volume.

Newton’s First Law of Motion states that in order for the motion of an object to change, a force must act upon it, a concept generally called inertia.

Newton’s Second Law of Motion defines the relationship between acceleration, force, and mass.

Newton’s Third Law of Motion states that any time a force acts from one object to another, there is an equal force acting back on the original object. If you pull on a rope, therefore, the rope is pulling back on you as well.