If we put a dipole that has the freedom to move, we put that dipole in an electric field, it will align itself with the field lines.

若我们将偶极释放到自由空间中，比如说放到电场里，他们会自动排序按同一方向。

麻省理工公开课 - 固态化学导论课程节选

So the minus vector is the same vector flipped over, pointing the opposite way.

因此负矢量即为同一矢量的翻转,指向相反的方向

耶鲁公开课 - 基础物理课程节选

Pick any two perpendicular directions Then the same entity, the same arrow which has an existence of its own, independent of axis, can be described by you and me using different numbers.

选取两个互相垂直的方向,这样同样的物体,同一矢量,并且是独立于坐标轴而存在的,可以被你和我用不同的数字来描述

耶鲁公开课 - 基础物理课程节选