主要区别-速度与加速度

速度和加速度都是与物体运动有关的矢量。速度和加速度的主要区别是速度是位移的变化率，加速度是速度的变化率。

什么是速度(velocity)？

If the position of a body can be represented by a position vector  , then the velocity of the body is defined as:

这给出了物体的瞬时速度，即在特定时间的速度。平均速度由下式给出：

速度是物体速度的大小。平均速度是身体行驶的总距离除以所用的时间。如果一个物体移动一段距离，回到它的起点，物体会有一个平均速度，但它的平均速度是0，因为它的位移是0。因为速度是一个矢量，速度的变化涉及到物体速度的变化或运动方向的变化。

These cars are accelerating since they are changing their direction of motion even though their speed may remain the same.

测量速度的国际单位制是ms-1。

什么是加快(acceleration)？

加速度定义为速度变化率：

根据牛顿第二运动定律，产生加速度需要合力。如果加速方向与身体运动方向相反，则身体处于减速状态，速度降低。

测量加速度的国际单位是ms-2。

Bodies falling under gravity close to Earth’s surface are approximately falling at a c***tant acceleration of about 9.81 m s-2. This acceleration is given the symbol . Sometimes,  is used as a unit to express acceleration. If a human is exposed to an acceleration higher than about  , blood may not flow into the brain the person might lose c***ciousness. This can happen, for example, in roller-coasters achieving high accelerati***. Astronauts and aviators need to be trained to stay c***cious at high- accelerati***. The video below shows a trainee losing c***ciousness from an acceleration of   (Note: GLOC stands for “-induced Loss Of C***ciousness”).

速度(velocity)和加快(acceleration)的区别

定义

Velocity is the rate of change of displacement:  .

Acceleration is the rate of change of velocity:  .

单位

速度单位为m s-1。

加速度单位为m s-2。

Image Courtesy:

“ Fontana, Calif. (May 1, 2004) – The U.S. Navy sp***ored Chevy Monte Carlo NASCAR…” by Chief Journalist Erik Schneider. (U.S. Navy photo ID 040501-N-1336S-037) [Public domain], via Wikimedia Comm***