You guys have also seen vectors, I'm pretty sure, but it is worth going over some properties and some may be new and some may be old.

我很肯定你们曾接触过矢量,但复习一下相关的性质是很有必要的,有些可能是新知识,有些是已经学过的

耶鲁公开课 - 基础物理课程节选