【简答题】在图所示平面系统中,已知:匀质圆盘A和匀质圆环B均重P,半径均为R,两者用杆AB相连,若均沿倾角为φ的斜面作纯滚动,略去杆AB重量,试求: (1)杆AB的加速度;(2)杆AB的内力;(3)轮A受到的摩擦力。
【多选题】blue / remembered the /she / at her grandmother’s home / small / statue .
D.
at her grandmother’s home
【判断题】碳原子数相同的烷烃中,支链多的烷烃熔点较低。
【单选题】The girl is doing _______homework at home .
【单选题】-----Hello, come in. . -----Thank you.
【简答题】(7分)化学与我们生活密切相关,请根据题意回答: (1)大米发霉了是绝对不能食用的。被霉菌污染后的大米,会产生致癌毒草素——黄曲霉菌素。有一种黄曲霉素B1的化学式是: C 17 H 12 O 6 ,它的相对分子质量是 , 该物质由 种元素组成,各元素的质量比是 。 (2)钠米材料氧化铝(铝元素为+3价)的化学式为 ,足球烯碳60的化学式为 。 (3)维生素C广泛存在于蔬菜水果中,人体缺乏维生素C会...
【单选题】—_______? —She's staying at home. [ ]
B.
What is she doing this weekend
D.
How long is Lily staying at home
【单选题】---She’s seldom asked to do housework at home, she? --- . Her parents are very busy with their work, so she has to do the laundry every day.