Principle of inertia
The principle of inertia states that if an object is left alone, is not disturbed, it continues to move with constant velocity in a straight line if it was originally moving, or it continues to stand still if it was just standing still. The principle of inertia was discovered by Galileo.
See also
Further reading
Feynman, RP; Leighton, RB; Sands M (1963) The Feynman lectures on physics, Volume 1, Narosa Publishing House, New Dehli, 665 p. (page 107).
