| Inertia is the tendency of objects in motion to stay in motion, and objects at rest to stay at rest, unless another force causes its speed or direction to change. It is one of the fundamental principles in classical physics, and described by Issac Newton in his first law of motion (also known as The Principle of Inertia). It is one of the primary manifestations of mass, a quantitative property of physical systems. Newton writes:
LAW I. Every object perseveres in its state of rest, or of uniform motion in a right line, except insofar it is compelled to change that state by forces impressed thereon. |
