能不能让让插图中的物块，按照题目的要求运动起来。 用于向学生演示完整的运动过程---**Question Stem:** 12. 如图，物块P固定在水平面上，其上表面有半径为R的1/4圆弧轨道。P右端与薄板Q连在一起，圆弧轨道与Q上表面平滑连接。一轻弹簧的右端固定在Q上，另一端自由。质量为m的小球自圆弧顶端A点上方的B点自由下落，落到A点后沿圆弧轨道下滑，小球与弹簧接触后，当速度减小至刚接触时的1/3时弹簧的弹性势能为2mgR，此时断开P和Q的连接，从静止开始向右滑动。g为重力加速度大小，忽略空气阻力，圆弧轨道及Q的上、下表面均光滑，弹簧长度的变化始终在弹性限度内。 **Other Relevant Text:** * Mathematical expression: 1/4 (describing the circular arc) * Mathematical expression: 1/3 (ratio of velocity) * Mathematical expression: 2mgR (elastic potential energy) **Chart/Diagram Description:** * **Type:** Schematic diagram illustrating a physics problem setup. * **Main Elements:** * **Block P:** A block labeled "P" is positioned on the left, fixed on a horizontal ground surface (indicated by parallel dashed lines). Its upper surface features a 1/4 circular arc track. * **Plate Q:** A thin, rectangular plate labeled "Q" is connected to the right end of block P. It extends horizontally to the right, also resting on the horizontal ground surface. The 1/4 circular arc track smoothly connects to the upper surface of Q. * **Spring:** A light helical spring is placed horizontally on the upper surface of plate Q. Its right end is fixed to Q, while its left end is free, facing towards the 1/4 circular arc. * **Points A and B:** * Point A is located at the top-left edge of the 1/4 circular arc track on block P. A small, solid sphere (representing the small ball) is depicted at point A. * Point B is positioned directly above point A, indicated by a vertical dashed line connecting A and B. Another small, solid sphere is shown at point B, representing the starting position of the ball. * **Labels:** "A", "B", "P", "Q". * **Relative Position and Direction:** Block P and plate Q are aligned horizontally on a flat surface. The arc on P curves downwards and to the right, smoothly transitioning to the flat surface of Q. The spring is to the right of the arc, on Q. Point B is vertically above point A. The overall setup implies motion from B, down the arc, and then onto Q to interact with the spring.