【单选题】如图所示,在一水平光滑绝缘塑料板上有一环形凹槽,有一带正电小球质量为m、电荷量为q,在槽内沿顺时针做匀速圆周运动,现加一竖直向上的均匀变化的匀强磁场,且B逐渐增加,则
【单选题】如图所示,两条不等长的细线一端固定在同一点,另一端分别拴两个带同种电荷的小球,两小球所带的电荷量分别为q1、q2,质量分别为m1、m2,当两小球静止时恰好处于同一水平线上,且α>β,则造成α>β的原因是 ( )
【单选题】如图所示,匀强电场的电场强度方向与水平方向夹角为30°且斜向右上方,匀强磁场的方向垂直于纸面(图中未画出).一质量为m、电荷量为q的带电小球(可视为质点)以与水平方向成30°角斜向左上方的速度v做匀速直线运动,重力加速度为g,则( )
【简答题】完形填空。 Bob is 1 American boy. He studies in a high school in Washington. He is four years old and he is in Grade 8 now. Bob wa s born 2 1984 in New York. He started school at th e age of six. He st...
【判断题】华山的断裂崩塌受到侵蚀以后花岗岩的表面形成了流纹岩。()
【简答题】Bob is 1 American boy. He studies in a high school in Washington. He is four years old and he is in Grade 8 now. Bob was born 2 1984 in New York. He started school at the age of six. He studied in...
【单选题】下列哪个阶段不是软件生存期三个阶段中的内容()。
【简答题】B Mr. Smith is from New York. He is in China for about 8 years. He teaches us English. His English classes are very interesting. We all like his classes very much. Mr. Smith has two children—Scott and...
【单选题】血型分二类,一类与人相同,如 A、B、O和Rh型,另一类是该属动物特有的如Arh、Crh、Drh,这类血型抗原能产生同族免疫,且不会发生新生仔溶血的动物是