1-1 What Macroeconomists Study Why have some countries experienced rapid growth in incomes over the past century while others stay mired in poverty? Why do some countries have high
§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)
§1-1 材料力学的任务及研究对象(The tasks and research objects of mechanics of materials) §1-2 变形固体的基本假设(The basic assumptions of deformable body ) §1-3 力、应力、应变和位移的基本概念 ( Basic concepts of force、stress、 strain and displacement) §1-4 杆件变形的基本形式 (The basic forms of deformation)