The physics of a hula hoop is determined primarily by the effect of the centripetal force acting on the hoop. However, the friction force on the hoop also plays a role. A simple experiment is described showing how an increase in the friction coefficient can help to prevent the hoop falling.

中文翻译：

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摩擦对呼啦圈的影响

呼啦圈的物理特性主要由作用在呼啦圈上的向心力的作用决定。但是，箍上的摩擦力也起作用。描述了一个简单的实验，该实验显示了摩擦系数的增加如何有助于防止环向下降。