截面的几何性质(Properties of Plane Areas) 附录I截面的几何性质 (Appendix I Properties of plane areas) 1-1截面的静矩和形心(The first moments of the area& centroid of an area) 1-2极惯性矩惯性矩惯性积(Polar moment of inertia Moment of inertia Product of inertia) 1-3平行移轴公式(Parallel-Axis- theorem) 1-4转轴公式(Rotation of axes)(Properties of Plane Areas) 附录Ⅰ 截面的几何性质 (Appendix Ⅰ Properties of plane areas) §1-1 截面的静矩和形心(The first moments of the area & centroid of an area) §1-4 转轴公式 (Rotation of axes) §1-2 极惯性矩 惯性矩 惯性积 (Polar moment of inertia Moment of inertia Product of inertia) §1-3平行移轴公式 (Parallel-Axis theorem)