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acceleration decrease(減加度速) 等唔等於 deceleration(負向加速)??

2006-12-23 18:38:43 · 3 個解答 · 發問者 harry 1 in 科學 其他:科學

3 個解答

acceleration 是加速度,一般指物件以每秒計的時間加速移動,加速度下降(acceleration decrease)是物件每秒加速慢下來,即是還在加速。

deceleation是減速,指物件不但沒有加速,相反在減速。

所以,acceleration decrease 不等於 deceleration。

2006-12-23 18:49:11 · answer #1 · answered by cyril 6 · 0 0

要明白什麼叫accleration 即加速率, 首先要知accleration其實係一個vector
First
Vector, 係乜黎呢? 
係有方向性的,呢個好重要
Then
GIVE you an example
你係條路上面加速向左行,咁你的acceleration係正定係負呢
Ans: 不是正也不是負
因為acceleration係vector, 你要定義左邊個方向係正先
例如,如果我定義剛剛那個situation, i let left direction as positive
hence a is positive, that mean it carry out positive acceleration or negative deceleration
but if i let right direction as negative
a is negative, that mean it carry out positive deceleration or negative acceleration

2006-12-23 21:55:32 · answer #2 · answered by Anonymous · 0 0

If you look on the physics point of view, the definition of acceleration is

acceleration = (final velocity - initial velocity)/time taken

In [acceleration decrease], the final velocity is still greater than the initial velocity, though the difference becomes smaller than before. That is, the magnitude of the acceleration is still positvie.

In [decceleration], or sometimes called retardation, the final velocity is smaller than the initial velocity, i.e. the difference of (final velocity - initial velocity) is negative and thus the magnitude of acceleration (i.e. decceleration) is negative.

Hence, acceleration decrease and decceleration means differently in physics.

2006-12-23 20:18:14 · answer #3 · answered by 天同 7 · 0 0

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