Unit 3 Tourism 1 The Great Wall, the symbol 2 The Palace Museum(故宫), the ForbiddenCity(紫禁城), wooden-structure-(木结构), building complex(建筑群), be enthroned(登基) 3 The Peking Man, skull(头颅), be unearthed(出土 4 terra-cotta- warriors and horses(兵马俑),The first Chin Emperors' Mausoleum(始皇陵),be dubbed as(被戏称为),the8 th wonder(第8大奇迹)
In this lecture, we consider the motion of a 3D rigid body. We shall see that in the general three dimensional case, the angular velocity of the body can change in magnitude as well as in direction, and, as a consequence, the motion is considerably more complicated than that in two dimensions. Rotation About a Fixed Point We consider first the simplified situation in which the 3D body moves in such a way that there is always a point, O, which is fixed. It is clear that, in this case, the path of any point in the rigid body which is at a