(11分)如图所示,在竖直放置的光滑半圆弧形绝缘细管的圆心处放一点电荷,将质量为m、带电荷量为q的小球从圆弧管水平直径的端点A由静止释放,当小球沿细管下滑到最低点时,对细管的上壁的压力恰好与球重相同,求圆心处的电荷在圆弧管内产生的电场的场强大小. 图8
--Who is late for class again? --________ you ask? Tim, of course.
--Shall I give you a ride to the Capital Airport? --Thank you.________.
--Kathy and her sister are so alike. --Yeah, I can’t tell one from ________.
The largest ever ________ 16th Asian Games is ________ huge success and the best ever in history.
Write an English composition in 120~150 words according to the instructions given below in Chinese. 就你读过的一本书,写一篇读后感。具体要求如下: ·写出书名及作者 ·简单介绍书中你最感兴趣的人物、情节或思想(三者选一即可) ·说明感兴趣的理由