Tuesday, March 12, 2013

Newton's Laws

Sir Isaac Newton's three laws of motion were first compiled in his work PhilosophiƦ Naturalis Principia Mathematica and published in 1687:

  • First law: If there is no net force on an object, then its velocity is constant. The object is either at rest (if its velocity is equal to zero), or it moves with constant speed in a single direction
  • 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 = m*a.
  • 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. Actio = Reactio.