Let's call it a massless spring.

我们叫它无质量弹簧。

We call that a massless string.

我们叫它无质量绳。

The Standard Model said they should be massless.

标准模型说他们应当没有质量。

It obeys Hooke's Law, and it is also nearly massless.

它遵循胡克定律，几乎是无质量的。

So you have three point masses, and they are connected with massless rods.

你们有个三角物体，它们由无质量棒相接。