这道题怎么解？---**Extracted Content:** **Question Stem:** 23. 如图 16 所示, 长 L 的细绳一端固定于 A 点, 另一端系一小球. 水平 x 轴的原点 O 位于悬点 A 的正下方 L/2 处. 现在 x 轴正方向上某处钉一钉子 P, 再将球拉到细绳处于水平的位置, 由静止释放, 要使球下摆后可绕钉子 P 在竖直平面内转动一周. 已知细绳能承受的最大拉力为球重的 7 倍, 不计空气阻力. 求钉子 P 应钉在 x 轴上的位置坐标范围. **Other Relevant Text:** 图 16 **Chart/Diagram Description:** * **Type:** Schematic diagram illustrating a physics problem setup. * **Main Elements:** * A fixed point A is shown with a wall support symbol above it. * A horizontal line representing a string of length L extends to the right from point A, with a small circle at the end representing a ball. * A vertical dashed line connects point A to point O. The distance between A and O is labeled L/2. * Point O is labeled and is the origin of a horizontal line extending to the right, which is labeled as the x-axis with an arrow indicating the positive direction and the label 'x'. * A point P is shown on the x-axis to the right of O, marked by a dot. * The diagram shows the initial position of the string and ball (horizontal) and the relative positions of A, O, P, and the x-axis. * The figure number "图 16" is present below the diagram.