铁棒会停在什么位置? 应选C。因为转轴正好通过铁棒的质心(重心),铁棒能在任何位置上都可以保持平衡。54°的角能三等分吗? 这是可以完成的:以顶点O为圆心,用适当半径画出一个圆,设圆周和两条射线的交点为A和B,如图所示。现在以B为圆心,以BO为半径,用圆规在圆周上连续截出A_1、A_2和A_3三个点。这时圆弧BA_1、A_1A_2和A_2A_3都是 Where does the iron bar stop? C should be selected. Because the shaft just passes through the center of mass (center of gravity) of the iron bar, the iron bar can maintain its balance at any position. Can the angle of 54° be tri-divided? This can be done: With the vertex O as the center, draw a circle with the appropriate radius, and set the intersection of the circle and the two rays as A and B as shown. Now take B as the center and BO as the radius, successively cut out three points A_1, A_2, and A_3 on the circumference with compasses. At this time, the arcs BA_1, A_1A_2, and A_2A_3 are all