A:4.5m/s
B:4m/s
C:4.2m/s
D:3m/s
⑴Is it hot?____ A. It's on the second floor.
⑵What's the weather like in Beijing?____ B. It's warm and sunny.
⑶Where is the library?____ C. Yes,we do.
⑷What time is it?____ D. No,it isn't.
⑸Do you have a computer room?____ E. It's 6 o'clock.
用量筒量取20mL水,俯视读数,则所量取水的实际体积( )
河南省开封市西北,有一座5A级风景区一清明上河园。有一片建筑高挂“瓦子”的标志,瓦子是北宋东京城里( )
如图所示,在竖直平面内有一边长为L的正方形区域处在场强为E的匀强电场中,电场方向与正方形一边平行.一质量为m、带电量为q的小球由某一边的中点,以垂直于该边的水平初速V0进入该正方形区域.当小球再次运动到该正方形区域的边缘时,具有的动能可能为( )