In the spring and summer,he says, he would expect the prevailing winds in Western Europe to come from the West or Southwest - which would mean that the ash would be pushed towards the Arctic or Siberia.

VOA: standard.2010.04.16

Newton is not going to come and tell you what force the spring will exert when it's pulled by some amount.

牛顿不会过来告诉你,弹簧被拉伸一定量时会产生多大的力

耶鲁公开课 - 基础物理课程节选