英语时差：动量（下）

Drop it right over the X and it will land somewhere past where you want it to be. The effect will be the same as if you had stood over the X and thrown the ball forward. To hit the X you need to drop the ball before you have reached it. And the faster you are moving, the earlier you need to let go. This is a difficult thing for a lot of people to believe. In one survey done on undergraduate students, about half of them argued that the ball can’t have any forward momentum if it’s just passively carried. True, the carried ball feels like it is sitting still, but don’t be fooled. From the point of view of someone standing by the X, the ball is moving as fast as you are.