You shoot something, you should know when it will land, where it will land, with what speed it will land, how high it will go.

抛出一个物体,我们要知道落地时间,落地位置,还有落地的速度,最高点的高度

耶鲁公开课 - 基础物理课程节选

So you should know when you look at a graph like this what it's doing.

因此当你看到这样一个图表时,要知道它是怎样运动的

耶鲁公开课 - 基础物理课程节选

That means, when I take two derivatives, I want to get a, then you should know enough calculus to know it has to be something like at^, and half comes from taking two derivatives.

也就是说,当我想求二阶导时,得到了a,你应该有足够的微积分知识,才能知道必须有类似at^的项,而这个1/2则是因为求了两次导数

耶鲁公开课 - 基础物理课程节选