Every body preserves in its state of being at rest or of moving uniformly straight forward, except in so far as it is compelled to change its state by forces impressed. A change in motion is proportio...Every body preserves in its state of being at rest or of moving uniformly straight forward, except in so far as it is compelled to change its state by forces impressed. A change in motion is proportional to the motive force impressed and takes place along the straight line in which that force is impressed. To any action there is always an opposite and equal reaction; in other words, the actions of two bodies upon each other are always equal and always opposite in direction.
