- 1. The act of accelerating. 2. The rate of increase in velocity per unit of time; commonly expressed in g units; also expressed in centimeters or feet per second squared. 3. The rate of increasing deviation from a rectilinear course. See radial a.. [see accelerator]- angular a. the rate of change of angular velocity; e.g., when a centrifuge rotor is speeding up, or when there is a simultaneous change in velocity and direction, as in an aircraft in a tight spin.- linear a. the rate of change of velocity without a change in direction; e.g., when the speed of an aircraft increases while flying a straight pathway.- radial a. the centripetal a. of a particle or vehicle moving along a curved path at a constant velocity; e.g., turning a curve in an automobile, pulling out of a dive, or performing a loop maneuver in an aircraft. In aviation, a. varies directly with the square of the air speed and inversely with the radius of the turn (a = V2r, where V is air speed and r is radius of turn).
* * *ac·cel·er·a·tion ik-.sel-ə-'rā-shən, (.)ak- n1) the act or process of accelerating: the state of being accelerated2) change of velocity also the rate of this change3) advancement in mental growth or achievement beyond the average for one's age
* * *ac·cel·er·a·tion (ak-sel″ər-aґshən) [L. acceleratio, from ad- intensification + celerare to quicken] 1. a quickening, as of the pulse rate or respiration. 2. in physics, the time rate of change of velocity; symbol a>.
Medical dictionary. 2011.