Even in the case of this spring, when you pull it, if you pull it to the right by some force.

甚至是在这样的弹簧问题中,当你拉它的时候,如果你用力向右拉

耶鲁公开课 - 基础物理课程节选

They seem to be going somewhere and there's this sort of force of pull or gravity in music having to do with some chords wanting to go to other chords.

和弦向某一个方向发展，就像有一股力量拉着它们,或者说音乐的重力吸引着它们，让一些和弦想行进成为另一些和弦。

耶鲁公开课 - 聆听音乐课程节选

It says, if you pull it to the right, so that x is positive, the spring will exert a force which is in the negative direction; that's why you have a minus sign.

就是说,如果你向右拉,x 取正值,弹簧产生的力方向为负,这就是这里用负号的原因

耶鲁公开课 - 基础物理课程节选