| New·ton's laws of motion (nōōt'nz, nyōōt'-) pl.n. The three laws proposed by Sir Isaac Newton to define the concept of a force and describe motion, used as the basis of classical mechanics. [After Isaac Newton.] |
The three laws that govern the motion of material objects. They were first written down by Isaac Newton in the seventeenth century and gave rise to a general view of nature known as the clockwork universe. The laws are: (1) Every object moves in a straight line unless acted upon by a force. (2) The acceleration of an object is directly proportional to the net force exerted and inversely proportional to the object's mass. (3) For every action, there is an equal and opposite reaction.
Note: Until the beginning of the twentieth century, these three laws, together with the laws of thermodynamics and Maxwell's equations, were thought to explain the entire physical universe.