来自《耶鲁大学开放课程：基础物理第4集第4集》

So that's the knowledge of the present.

这是当前已知的条件
The question is, when I let it go,

问题是当我松手的时候
what's this guy going to do?

这个物体会做如何运动
That's the typical physics problem.

这是一个典型的物理问题
It can get more and more complex.

这个问题可以变得更加复杂
You can replace the mass by a planet;

你可以用一颗行星来替换这个物体
you can replace the spring by the Sun,

用太阳替换弹簧
which is attracting the planet;

它吸引着行星
you can put many planets,

你可以放置许多行星
you can make it more and more complicated.

可以让这个问题越来越复杂
But they all boil down to a similar situation.

但他们都可以归结为同一个相似的情况
I know some information now

现在已知一些条件