【简答题】均匀磁场中,一重量为W的物体经无摩擦滑轮拉着金属杆,使金属杆在相距为,的平行导线上滑动(不计摩擦),双线一端接电阻R,导线平面与 垂直,如图6.5所示。
【简答题】I was ten when I first sat with my grandmother behind the cashier(收银台)in her general store. 小I was ten when I first sat with my grandmother behind the cashier(收银台)in her general store. ____ 小题1:____...
【单选题】如图所示,用甲、乙两个滑轮组来提相同重物G,甲图中两个动滑轮共重5N,乙图中一个动滑轮重3N,不计摩擦和绳重,则两个滑轮组的机械效率( )
【简答题】That day I was later for school, so Mom offered me a 36 . I sat beside her in our car, daydreaming about my 37 . I’d be graduating from high school in a few months. I’d leave high school behind and do...
【判断题】图中接触面不计摩擦,物体AD在四处受接触面约束反力作用。( )
【单选题】对设计站历年水位流量关系曲线对比分析的目的是
【判断题】三相异步电动机在制动状态下运行时,转差率 s>1 。
【单选题】She sat at her desk, with her eyes ________ on the book, ________ in its plot. [ ]
【多选题】关于单向板分布筋描述正确的是 ( ) 。
C.
将作用于板上的集中或局部荷载分散给更大范围的受力筋承受
E.
对四边支承板,可承受在计算中未计及但实 际存在的长跨方向的弯矩
【单选题】如图所示的装置中,不计滑轮摩擦,当水平向右拉力F=5N时,物体m恰能匀速运动,那么物体受地面的摩擦力的大小为( )。