The cycle frequency of jet fluid swing is half of that of tangential circle rotation.

相应切圆呈周期性旋转，射流摆动也具有周期性，该周期是切圆旋转周期的一半。

youdao

The quality of this transition is best visualized by a straight line drawn between two circles: the line's only point of contact with each circle is tangential.

用最明显的图形来描述这个过渡的特性就是：当在两个圆之间绘制一条直线，直线与每个圆只有一个交点时，那么这条线就是两个圆的切线。

youdao

I'm asking what's the tangential speed as it moves along the circle?

它在做圆周运动时,切向速度是多少

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