"Isaac Newton defined inertia as his first law in his Philosophić Naturalis Principia Mathematica, which states:
The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line."
mike hallam (with thanks to Wiki.)
Last edited by mikehallam; 10th December 2012 at 10:13.