뉴턴의 운동법칙

뉴턴의 운동법칙은 다음과 같다.

Law I: Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.^[28]

뉴턴이 본인의 저서 프린키피아에 서술한 내용은 우리가 현재 교과서에서 배우는 내용과 다르다.

Law II: The alteration of motion is ever proportional to the motive force impress'd; and is made in the direction of the right line in which that force is impress'd.

The change of momentum of a body is proportional to the impulse impressed on the body, and happens along the straight line on which that impulse is impressed.

질량이 변하지 않는 경우에만

이 식은 오일러가 처음으로 표현하였다고 한다.

Law III: To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.