acceleration

加速

物が動く速さが変わること。

やさしい英語で： A change in how fast something moves.

• The sudden acceleration pushed me into my seat.
• This car offers smooth acceleration.
• Passengers felt the plane’s acceleration during takeoff.

よく使う表現： sudden acceleration, rapid acceleration, smooth acceleration

加速

動きが速くなることや、物事の進む勢いが増すこと。

やさしい英語で： An increase in the speed of movement or in how quickly something happens.

• We noticed an acceleration in growth.
• New equipment allowed the acceleration of production.
• The acceleration of change left many workers struggling to adapt.

使い方： acceleration of something (The acceleration of the project required extra staff.); acceleration in something (The report predicts an acceleration in economic growth.)

類義語： speeding up, quickening

反対語： deceleration, slowdown

よく使う表現： acceleration of growth, rapid acceleration, economic acceleration

加速度

一定の時間に速さがどれだけ増えるかを表す量。

やさしい英語で： The amount by which speed or velocity increases over a given time.

• The car’s acceleration was two metres per second squared.
• We measured the rocket’s acceleration.
• Greater force produces greater acceleration for the same mass.

よく使う表現： constant acceleration, average acceleration, acceleration of something, instantaneous acceleration

加速度

動く物の速さや向きが、時間とともに変わる割合。

やさしい英語で： The rate at which the speed or direction of a moving object changes.

• We measured the acceleration of the car.
• The force produces an acceleration toward the center.
• Even at constant speed, a change in direction involves acceleration.

よく使う表現： constant acceleration, acceleration due to gravity