| 释义 |
acceleration|æksɛləˈreɪʃən|
[ad. L. accelerātiōn-em, n. of action f. accelerā-re: see accelerate a. and -ion1. Cf. mod.Fr. accélération.]
1. a. The action or process of accelerating, quickening or hastening. Also spec. of charged particles (cf. accelerate v. 1 c).
1531Elyot Governour (1834) 117 Who beholding..the acceleration or haste to his [Cæsar's] confusion, caused by his own edict or decree, will not commend affability. 1663Cowley Verses & Essays (1669) 45 A Garden, destined to the tryal of all manner of Experiments concerning Plants, as their Melioration, Acceleration, Retardation, Conservation. 1732Arbuthnot Rules of Diet 266 Those things which take off the Causes of Acceleration retard the Motion of the Blood. 1822J. Imison Sc. & Art I. 84 But the friction of the teeth and the resistance of the air check this acceleration. 1909H. A. Lorentz Theory of Electrons 120 The radiation from a single electron..is determined by the acceleration. 1932[see accelerating vbl. n.]. 1942Stranathan Particles vii. 294 The negative linear accelerations suffered by the electrons as they strike the target.
b. The process of increasing the speed of a motor-engine or -vehicle; hence, capacity of being accelerated, as an attribute of the vehicle itself.
1901Motor-Car World II. 238/1 Instantaneous acceleration when the clutch is once more engaged. 1926Daily News 18 May 4/5 There are many British cars with fine acceleration.
2. The condition of being accelerated or hastened; increased speed.
1534Ld. Berners G. Boke of M. Aurel. (1546) F. viij. b, Gret acceleracion in busynesses nowe presente maketh greate inconueniences in tyme to come. 1784Johnson in Boswell (1816) IV. 455 No, sir; you cannot conceive with what acceleration I advance towards death.
3. The extent to which anything is accelerated; in Nat. Philos. the rate of increase of velocity per unit of time. uniform acceleration or constant acceleration: the unvarying amount per second added to the velocity or rate at which a body is moving, e.g. under the influence of gravity.
1656tr. Hobbes's Elem. of Philos. (1839) 232 The body will be carried through the same strait line..provided it have like acceleration. 1677Hale Prim. Orig. Man. 5 There be many things touching Matters Physical..as concerning the degrees of acceleration of Motion. 1794G. Adams Nat. & Exper. Phil. III. xxvii. 118 The law of acceleration, in falling bodies, was not discovered till the time of Galileo. 1876Tait Rec. Adv. in Phys. Sc. xiv. 352 Rate of change of velocity is called in kinematics, acceleration. 1879Thomson & Tait Nat. Phil. I. i. §28 The velocity of a point is said to be accelerated or retarded according as it increases or diminishes, but the word acceleration is generally used in either sense, on the understanding that we may regard its quantity as either positive or negative.
4. Astr. and Physics. Acceleration of the fixed stars; the time (3′ 55·9{pp}) which the stars gain upon the sun in passing the meridian each day, or by which the sidereal day is shorter than the solar, due to the advance of the earth in her orbit while revolving on her axis. Of the planets, the increased velocity with which they advance from aphelion to perihelion. Of the moon, an increase (of about 11{pp} in the century) in the rapidity of the moon's mean motion, discovered by Halley. Of the tides, the amount by which from special causes, high or low water occurs at any place before the calculated time.
1849M. Somerville Connex. of Phys. Sc. §5. 43 This secular increase in the moon's velocity is called the Acceleration.
▸ Educ. (orig. and chiefly N. Amer.). The action or process of advancing a student through a course of education more rapidly than is usual, esp. because of exceptional ability; (also) rapid educational progress of this kind.
1916L. M. Terman Measurem. of Intelligence ii. 27 Teacher attributed school acceleration to ‘studiousness’ and ‘delight in school work’. It would be more reasonable to infer that these traits are indications of unusually superior intelligence. 1920Jrnl. Educ. Res. 2 603, I found that in School A..the amount of acceleration was very nearly the same as was found in many of the schools in the poorer sections. 1949S. L. Pressey Educ. Acceleration ii. 8 The accelerated students..seem to have profited to some extent by acceleration. 1964B. Fine Stretching their Minds 19 ‘Acceleration’ became fashionable—meaning either old-fashioned ‘skipping’ or the modern ‘multiple-track’ plan (in racing terms, a slow track for the average student, a fast track for the superior). 1996Independent 30 Jan. 14/7 Acceleration or fast-tracking (to use the American term) of bright children in schools..is rare in continental Europe, where the academic success of the children does not appear to have suffered. |