绕定轴 O 转动的皮带轮,时刻 t ,轮缘上的 A 点速度大小为 v A =50 cm/s ,加速度大小 a A =150 cm/s2 ;轮内另一点 B 的速度大小 v B =10 cm/s ,已知这两点到轮心距离相差 20 cm ,此时刻轮的角速度为( ) ,角加速度为( ) ,点 B 的加速度为( )
【单选题】听力原文:W: What do you think of the objective of monetary policies? M: It is to maintain the stability of currency and thereby promote economic growth. Q: What is the objective of monetary policies? (12)
【单选题】Once objectives and policies are established, the manager just let other people perform. the activities necessary for achieving the goal without doing anything else himself.