a frame of reference in which a body remains at rest or moves with constant linear velocity unless acted upon by forces: any frame of reference that moves with constant velocity relative to an inertial system is itself an inertial system.
a frame of reference within which bodies are not accelerated unless acted upon by external forces Also called inertial reference frame
noun 1. a U.S. two-stage, solid-propellant rocket used to boost a relatively heavy spacecraft from a low earth orbit into a planetary trajectory or an elliptical transfer orbit. Abbreviation: IUS.
- Inertia-reel seat belt
noun 1. a type of car seat belt in which the belt is free to unwind from a metal drum except when the drum locks as a result of rapid deceleration
- Inertia selling
noun 1. (in Britain) the illegal practice of sending unrequested goods to householders followed by a bill for the price of the goods if they do not return them
- Inertia time
inertia time n. The interval elapsing between the reception of the stimulus from a nerve and the contraction of the muscle.