Newton's laws of motion

(redirected from Newton's third law)
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

Newton's laws of motion

three laws that relate the forces and motions of bodies or objects (from the viewpoint of a fixed observer), first proposed by Isaac Newton. (1) An object will remain at rest or continue with constant velocity unless acted on by an unbalanced force. (2) The rate of change of momentum (or acceleration for a body/object of constant mass) is proportional to, and in the same direction as, the force applied to it (force = mass ×1 acceleration). (3) When two objects are in contact, the force applied by one object on the other is equal and opposite to that of the second object on the first (for every action, there is an equal and opposite reaction).


principle or rule
  • Davis' law soft tissues' tendency to shorten and contract unless subject to frequent stretching

  • Hilton's law a joint and its motive muscles (+ insertions) are all supplied by the same nerve

  • Hook's law tissue strain (i.e. change in length) is directly proportional to applied compressive or stretching stress, so long as tissue elasticity (recoil ability) is not exceeded

  • inverse-square law radiation intensity is inversely proportional to square of distance from radiation source (rad = κ1/cm2)

  • law of excitation muscle tissue contracts in direct proportion to stimulating current strength

  • Newton's first law; law of inertia an object at rest will not move until acted upon by a force; an object in motion will remain in motion at constant velocity until acted on by a net force

  • Newton's second law; law of acceleration acceleration is directly proportional to applied force and indirectly proportional to object mass (i.e. force = mass × acceleration)

  • Newton's third law; law of reciprocal actions to every action there is an equal and opposite reaction; i.e. a body is maintained at rest by equal and opposing forces

  • Pascal's law a fluid at rest transmits pressure equally in every direction

  • Poiseuille's law vascular blood flow is inversely proportional to fourth power of vessel radius (i.e. the narrower the vessel, the greater the resistance to flow)

  • Starling's law the greater the stretch imposed on a circular muscle (e.g. muscle layer of an artery), the greater its reciprocal recoil and contraction

  • Wolff's law bone function changes cause bone structure modification (see bone modelling)

Mentioned in ?
References in periodicals archive ?
Torque, just like Newton's Third Law, can be seen everywhere around us from see-saws to spinning tops to a busy mechanic tightening a bolt with the help of a wrench.
The only thing I could bank on was Newton's third law of motion and how it worked itself out so beautifully in the Bible.
Newton's Third Law may be deduced from the law of interaction of section 3 and in particular from equation (24) of corollary III.
Now we can explain the treatment of Newton's third law.
Newton's third law of motion has an analog in the realm of public policy, law, and politics.
For certain types of NEOs, by Newton's Third Law, the jet stream created would alter the object's solar orbit, hopefully converting an Earth impact to a near miss," Matloff stated.
Law Definition Example Newton's First Law Newton's Second Law Newton's Third Law
What, I asked myself, about Newton's Third Law of Motion?
Newton's third law of motion says for every action there is an equal and opposite reaction.
Pupils watched a skeleton pedalling a bicycle to see how their leg bones rely on muscles, ran races to test their reaction time and put Newton's Third Law to the test by jumping up and down.
The relevant scientific principle is Sir Isaac Newton's third law of motion - the law of reaction.