and you will get an equation that the only unknown will be d,

你会得到一个仅含有一个未知数 d 的方程
and you solve for a d and it'll tell you how much it moves.

解出 d 就能知道马车移动的距离
Anybody have a question about how you attack this problem?

还有谁对这个问题的解法有疑问
Find the center of mass before, find the center of mass after,

分别表示出初状态和末状态的质心的位置
equate them and that linear equation will have one unknown,

令它们相等就得到了一个一元一次方程
which is the d by which the carriage has moved

就是马车移动的距离 d
and you can solve for it.

你可以解出它来
Okay, here's another problem.

好的这里有另外一个问题
Here is a shore, and here is a boat;

这是河岸这是一艘船
maybe I'll show the boat like a boat, here it is,

我该把船画得更像船就像这样
okay that's the boat.

好这就是那艘船
Now, you are here.

现在你在这里