law of motion

Definition of law of motion

1 : a statement in dynamics: a body at rest remains at rest and a body in motion remains in uniform motion in a straight line unless acted upon by an external force

called also Newton's first law of motion

2 : a statement in dynamics: the acceleration of a body is directly proportional to the applied force and is in the direction of the straight line in which the force acts

called also Newton's second law of motion

3 : a statement in dynamics: for every force there is an equal and opposite force or reaction

called also Newton's third law of motion

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Cite this Entry

“Law of motion.” Dictionary, Merriam-Webster, Accessed 14 Aug. 2022.

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