圆周运动作为一种特殊的曲线运动是高中物理必修二中的重点内容,考查较多的是两类圆周运动,一类是水平面内的匀速圆周运动,另一类是竖直平面内的圆周运动.本文通过一道课后补充练习为例子,讨论被光滑圆环约束着的小环真正的运动情况,从而加深对圆周运动知识的理解和掌握,同时也增加对试题设置的合理性及解答的科学性的认识. Circular motion as a special curve movement is the key content of high school physics compulsory two, two types of circular motion are examined, one is the constant circular motion in the horizontal plane and the other is the circular motion in the vertical plane In this paper, we will take a supplementary lesson after class as an example to discuss the real movement of the ring restrained by a smooth ring, so as to deepen the understanding and mastery of the knowledge of circular motion and to increase the rationality of the test questions and answer the scientific Sexual understanding.