But because gravity makes the ball's trajectory a parabola, the air pushing against the ball changes directions as it flies.
但是因为重力使球的轨迹呈抛物线，所以当球飞行时，推动球的空气改变了方向。
Crash Course 综合篇
But there’s one more question: How does the ball’s position change over time?
但还有一个问题：球的位置如何随时间变化？
Crash Course Physics 速成课物理
But there's one more question: How does the ball's position change over time?
如何？ 球的位置会随着时间而改变吗？
英语百科
Ball change
Ball change is a dance move that consists of two steps: a partial weight transfer on the ball of a foot (placed e.g., behind), followed by a step on the other foot. This action has a syncopated feeling and counted &1, or &2, or a1, or a2, etc., i.e., the "ball" step splits off the end of the previous beat.