Now, gravity, well force, is equal to mass times acceleration, g and the acceleration due to gravity is g.

是重力，等于质量乘以加速度，由重力导致的加速度是。

麻省理工公开课 - 热力学与动力学课程节选

It knows that this particle happened to have a height of 15, at the time of 0, and a velocity of 10, and it is falling under gravity with an acceleration of -10.

这个质点恰好处在高度为15的地方,零时刻,初速为10,并在重力作用下以-10的加速度下坠

耶鲁公开课 - 基础物理课程节选

Then the acceleration of the planet is the force of gravity between the planet and the Sun, which Newton will tell you is directed towards the Sun and it depends on how far you are.

行星的加速度源自,行星和太阳之间的作用力,牛顿认为这个力指向太阳,它的大小取决于行星离太阳有多远

耶鲁公开课 - 基础物理课程节选

You can see that if a was equal to g, your downward acceleration is that of gravity, namely the cable has snapped in the elevator, Then you don't feel any weight.

你会发现如果 a 等于 g,你下降的加速度就是重力加速度,也就是电梯的绳索断了,那时你会完全失重

耶鲁公开课 - 基础物理课程节选

Conversely, if you get an answer and it doesn't seem to make sense, then you've got to go back and ask, am I violating some of the assumptions, and here you will find the assumption that the particle had that acceleration a is true as long it's freely falling under gravity but not when you hit the ground.

反过来说,如果你得到一个结果,发现似乎是错的,那么你就应该回过头来问问自己,我是不是违反某些前提了,这个模型中,你就发现,只要质点在重力作用下自由下落,质点具有加速度a的前提是正确的,但是落地后就不成立了

耶鲁公开课 - 基础物理课程节选