If it's not, then you're going to have trouble describing it using thermodynamic properties.

如果它不是，那么用热力学性质去,描述它就要有麻烦了。

麻省理工公开课 - 热力学与动力学课程节选

If I'm now working in one dimension, it's obvious because I'm not using any vectors.

假设我现在只考虑一维的情形,这很明显,因为我没有用矢量

耶鲁公开课 - 基础物理课程节选