【简答题】A.The person who has the strong will. B.The person who has attended the school. C.The person who can pass the test of arithmetic. D.The person who can work at computers quickly after a two-day t...
【单选题】图示两均质细杆 OA 与 AB 铰接于 A ,在图示位置时, OA 杆绕固定轴 O 转动的角速度为 w , AB 杆相对于 OA 杆的角速度亦为 w , O 、 A 、 B 三点位于同一铅直线上。已知 OA 和 AB 两杆的质量均为 m ,它们的长度均为 L ,则该系统此时对 O 轴的动量矩大小 L O 为 ( ) 。