2. Three kinds of special Speeds p389 (1) The Average speed算术平均速率 8/T 7=vf(0)d V元m KT RT 7≈1.60 =1.60 VM2. Three kinds of special Speeds p389 (1) The Average Speed 算术平均速率: m kT f π 8 ( )d 0 = =   v v v v M RT m kT v 1.60 =1.60