if I put them on the--affix them to the ceiling that way

如果我把它们粘在天花板上
and attach the weight, what would happen?

并挂上砝码会发生什么呢
They would lengthen; they'd get longer

它们会被拉长它们会变得更长
because they're exposed to that weight.

因为它们受到砝码的拉力作用
I've applied a force and I've experienced a deformation.

我施加一个外力就能观察到形变
I've applied a force and the material has deformed.

我施加一个外力材料就会有形变
I'm going to quantify that, and I can quantify that

我要将其量化本例中我可以相当轻松地
fairly easily because I chose a simple material

进行量化因为我选了一种简单的材料
that had a constant cross-sectional area from the top to the bottom.

从顶端到底部其横截面积都是固定不变的
I'm going to assume that that cross-sectional area doesn't change

假设它发生形变时横截面积不变
when it deforms, but I hang the weight on it and the length increases.

但我挂上砝码时其长度增加了
The length is now L + ΔL.

现长度就是 "L + ΔL"