A reference frame in which the observers are not subject to any accelerating force. In Special Relativity, time measurements in inertial frames that are not at rest with respect to each other are not equivalent; each inertial frame must have its own time coordinate, the value of which is the time as read off a standard clock at rest in that frame. Also called inertial frame of reference, inertial reference frame, inertial system. Compare non-inertial frame. See also Special Relativity.
- Inertial fusion
noun 1. (physics) a type of nuclear fusion in which the inertia of matter enables it to fuse by impact, as by pulses of laser radiation or high-energy charged particles, rather than by high temperature
noun, Navigation. 1. a guidance system for an aerospace vehicle, in which self-contained devices determine the vehicle’s course on the basis of the directions and magnitudes of the accelerations it undergoes in flight. noun 1. a method of controlling the flight path of a missile by instruments contained within it. Velocities or distances covered, computed […]
noun, Physics. 1. the mass of a body as determined by the second law of motion from the acceleration of the body when it is subjected to a force that is not due to gravity. 2. the measure of the property of inertia. Compare , (def 2a), . noun 1. the mass of a body […]
- Inertial observer
noun 1. a hypothetical observer who is not accelerated with respect to an inertial system. Newton’s laws of motion and the special theory of relativity apply to the measurements which would be made by such observers