We select(选择)one arbitrary(任意) point p in the body whose circular motion can represents the motion of the entire body and use its circular plane as a reference to analyze ■■■■■■ ∷P (分析) the rotation of the Q rigid body around the fixed axis. 轴
We select （ 选 择 ） one arbitrary(任意） point P in the body whose circular motion can represents the motion of the entire body and use its circular plane as a reference to analyze （分析） the rotation of the rigid body around the fixed axis. y x 0 V r P P Q 轴
(2) Kinematics of rotation of a rigid body around a fixed axis is the same as the circular motion of ■■■即■圆 a particle that we discussed in chapter 1. Q Representative(代表)P: ① Angular position 6 」轴 ② Angular displacement△e d Angular speed o dt do d e Angular acceleration B== dt dt
（2）Kinematics of rotation of a rigid body around a fixed axis is the same as the circular motion of a particle that we discussed in chapter 1. Representative(代表） P : ① Angular position ② Angular displacement Angular speed dt d = = = t dt d d d 2 Angular acceleration P Q 轴
描述刚体定轴转动的物理量 Angular displacement d 8 de Angular speed 0= dt do de Angular acceleration B dt dt
描述刚体定轴转动的物理量 Angular displacement d Angular speed dt d = 2 t dt d d d 2 Angular acceleration = =
(4) Relation between two kinds of quantity 6,46,0,B 9 △s stn s=e ⑦ Br
（4）Relation between two kinds of quantity r s 2 = = = = t an a r r V r y x 0 V r P , , , t an r, s,V , a
85-2 Torque The Law of Rotation Rotational Inertia 力矩 转动定理 转动惯量 1. Torque Does a force make a rigid body rotate? depending on its magnitude and acting position. Torque (力矩)! Based on(根据) the concept of torque of a force acting on a particle with respect to a fixed point in 84-4), we can define the torque of a force acting on a rigid body
§5-2 Torque The Law of Rotation Rotational Inertia 力矩 转动定理 转动惯量 1. Torque Based on(根据) the concept of torque of a force acting on a particle with respect to a fixed point ( in §4-4), we can define the torque of a force acting on a rigid body. Does a force make a rigid body rotate? depending on its magnitude and acting position. Torque （力矩）! F F