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

Then, you've got to say, "What do I have to know about this object at the initial time?

然后,也许你会问,我需要知道物体初始状态的哪些信息呢

耶鲁公开课 - 基础物理课程节选

One way to say it is, every body will continue to remain in a state of rest or uniform motion in a straight line.

另外一种说法是,任何物体都会继续保持静止,或匀速直线运动的状态

耶鲁公开课 - 基础物理课程节选

It's very clear you don't need a force if something is doing nothing, just sitting there.

显而易见,如果物体没有运动,只是静止状态,那是不需要力的

耶鲁公开课 - 基础物理课程节选

I told you once you know the free parameters, R0 and v0, you know everything about the future of the object.

一旦给定自由参量 R0 和 v0,你就能知道这个物体之后的运动状态

耶鲁公开课 - 基础物理课程节选