It's not meant to be more than five, ten minutes of work, but the point of the question, -15, 20 minutes of work, but the point of the question is to motivate people to keep up with the material and do the readings.

几分钟就能完成,这个作业的目的,要十几到二十分钟完成吧,这个作业的目的在于激励大家,跟上课程的进度并去阅读材料

耶鲁公开课 - 心理学导论课程节选

For the simplest context in which one can motivate a vector and also motivate the rules for dealing with vectors, is when you look at real space, the coordinates x and y.

对于最简单的情况,我们能用矢量,以及相关的规则来处理的,是实空间,x-y 坐标系

耶鲁公开课 - 基础物理课程节选