You simply want to describe things the way they are and then dynamics tells you how they changed and why they changed.

你只是单纯描述物体的实际状态,而动力学则是解释它们运动的方式和原因的

耶鲁公开课 - 基础物理课程节选

Because any velocity I ascribe to a particle or an object, you will add a certain constant to it by the law of composition of velocity.

因为我描述的任何一个质点或者物体的速度,你都要根据速度叠加法则,给它加上某个常数

耶鲁公开课 - 基础物理课程节选

So what we would like to do is to describe what the object does by drawing a graph of time versus space and the graph would be something like this.

然后我们要做的就是描述这个物体的运动,通过画一个"x-t"图,画出来的图就像这样

耶鲁公开课 - 基础物理课程节选