acceleration

/əkˌseləˈreɪʃn/ (bre, ipa) · /əkˌseləˈreɪʃn/ (ame, ipa) · /ik-ˌse-lə-ˈrā-shən (ˌ)ak-/ (ame, mw)

acceleration — noun

1. the way a car, train, or other moving thing builds up speed, or how quickly it c

1.名詞B2
釋義

the way a car, train, or other moving thing builds up speed, or how quickly it can do this from a stop.

例句

The new electric taxi has smooth acceleration from a standstill at every traffic light.

collocation: smooth / quick / rapid acceleration

Diego was thrown back into his seat by the rocket's sudden acceleration.

pattern: thrown back by + acceleration

同義詞
  • pickup

    informal, mostly American, used for cars

  • speed-up

    informal; not used as commonly for vehicles

反義詞

文法句型

acceleration of [vehicle/object]

acceleration from X to Y

用法筆記

Often used with cars, planes, and other vehicles when talking about how fast they pick up speed. Frequently follows adjectives like 'smooth', 'sudden', 'rapid', or 'slow'.

常見錯誤

❌The car has a good speed of acceleration.
✅The car has good acceleration.
💡'acceleration' already includes the idea of speed; no need to add 'speed of'.

2. a faster pace at which an event, change, or trend happens, compared with how it

2.名詞C1
釋義

a faster pace at which an event, change, or trend happens, compared with how it was happening before.

例句

Climate scientists warned of a clear acceleration in the melting of Greenland's glaciers.

pattern: acceleration in + noun phrase

The pandemic caused a sharp acceleration of online shopping in many small towns.

pattern: acceleration of + noun phrase

同義詞
  • quickening

    more literary; common with the heart, pulse, or pace of events

  • speeding up

    informal verbal phrase used in everyday speech

反義詞
  • slowdown

    a drop in the pace of an activity or trend

  • decline

    a fall in level rather than just in pace

文法句型

acceleration in [process/trend]

acceleration of [activity]

用法筆記

Distinguish from sense 1 by checking the subject: if the noun describes a process or change (growth, decline, shopping, loss) rather than a moving object, this sense applies. Often paired with 'sharp', 'rapid', 'dramatic', or 'sudden'.

常見錯誤

❌There is a big acceleration to online learning.
✅There is a big acceleration of online learning.
💡use 'of' before the activity that is speeding up.

3. in physics, a measure of how fast a moving thing's velocity is changing each sec

3.名詞C1
釋義

in physics, a measure of how fast a moving thing's velocity is changing each second, taking into account both speed and direction.

例句

The students measured the acceleration of a steel ball as it rolled down a wooden ramp.

pattern: acceleration of + object

On Earth, the acceleration due to gravity is about 9.8 metres per second squared.

fixed phrase: acceleration due to gravity

同義詞
反義詞
  • deceleration

    negative acceleration, when an object slows down

文法句型

acceleration of [object]

acceleration due to [force]

用法筆記

Only sense that includes changes in direction, not just changes in speed. Subject is usually a physical object being studied or measured. Common in school physics and engineering contexts.

常見錯誤

❌The car has acceleration of 60 kilometres per hour.
✅The car has an acceleration of 2 metres per second squared.
💡physics acceleration is measured in distance per time squared, not in speed units.