Newton's Laws of Motion

Newton's laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces. They have been expressed in several different ways over nearly three centuries, and can be summarized as follows:

  1. First law: If an object experiences no net force, then its velocity is constant: the object is either at rest (if its velocity is zero), or it moves in a straight line with constant speed (if its velocity is nonzero).
  2. Second law: The acceleration a of a body is parallel and directly proportional to the net force F acting on the body, is in the direction of the net force, and is inversely proportional to the mass m of the body, i.e., F = ma.
  3. Third law: When a first body exerts a force F1 on a second body, the second body simultaneously exerts a force F2 = −F1 on the first body. This means that F1 and F2 are equal in magnitude and opposite in direction.

The three laws of motion were first compiled by Sir Isaac Newton in his work Philosophiæ Naturalis Principia Mathematica, first published in 1687. Newton used them to explain and investigate the motion of many physical objects and systems. For example, in the third volume of the text, Newton showed that these laws of motion, combined with his law of universal gravitation, explained Kepler's laws of planetary motion.

Read more about Newton's Laws Of Motion:  Overview, Newton's First Law, Newton's Third Law, Importance and Range of Validity, Relationship To The Conservation Laws

Famous quotes containing the words motion, newton and/or laws:

    Thence, flow! conceit and motion to rehearse
    Pastoral terrors of youth still in the man,
    Torsions of sleep, in emblematic verse
    Rattling like dice unless the verse shall scan
    All chance away....
    Allen Tate (1899–1979)

    Where the statue stood
    Of Newton with his prism and silent face,
    The marble index of a mind for ever
    Voyaging through strange seas of thought, alone.
    William Wordsworth (1770–1850)

    The life of a good man will hardly improve us more than the life of a freebooter, for the inevitable laws appear as plainly in the infringement as in the observance, and our lives are sustained by a nearly equal expense of virtue of some kind. The decaying tree, while yet it lives, demands sun, wind, and rain no less than the green one. It secretes sap and performs the functions of health. If we choose, we may study the alburnum only. The gnarled stump has as tender a bud as the sapling.
    Henry David Thoreau (1817–1862)