如图所示,在竖直向上的匀强电场中,一根不可伸长的绝缘细绳的一端系着一个带电小球,

题型:选择题

问题:

如图所示,在竖直向上的匀强电场中,一根不可伸长的绝缘细绳的一端系着一个带电小球,另一端固定于O点,小球在竖直平面内做匀速圆周运动,最高点为a,最低点为b.不计空气阻力,则(  )

A.小球带负电

B.电场力跟重力平衡

C.小球在从a点运动到b点的过程中,电势能减小

D.小球在运动过程中机械能守恒

考点:机械能守恒定律电势能
题型:选择题

This is a song millions of Americans will hear this New Year’s Eve. It is called Auld Lang Syne (《友谊地久天长》). It is the traditional music played during the New Year’s celebration. Auld Lang Syne is an old Scottish poem. It tells about the need to remember old friends.

The words “auld lang syne” mean “old long since”. No one knows who wrote the poem first. However, a version by Scottish poet Robert Bums was published (出版) in 1796. The words and music we know today first appeared in a songbook three years later.

The song is played in the United States mainly on New Year’s Eve. The version (译文) you are hearing today is by the Washington Saxophone Quartet. As we end our program with Auld Lang Syne. I would like to wish all of our radio friends a very Happy New Year! This is Buddy Thomas.

1. Millions of Americans will hear the song named _______________________this New Year’s Eve.

2. ______________________________ is introducing Auld Lang Syne to us.

3. Auld Lang Syne is an old Scottish poem about________________________________.

4. The song is played ________________________________on New Year’s Eve.

5. A version by Scottish poet Robert Bums was published (出版) in ________________________ .

题型:选择题

男,36岁,自3楼跌下,左腹部跌伤,左第6、7、8肋骨骨折,2小时后入院。诊断为脾破裂、肠破裂。入院时意识模糊,体温38.5℃,皮肤青紫,肢端冰冷,脉搏细弱,血压70/50mmHg。全腹压痛、反跳痛,无尿。

该病人不宜首先考虑的是()

A.急性肾衰竭

B.中度感染性休克

C.重度感染性休克

D.重度低血容量休克

E.中度低血容量休克

题型:选择题

按相关规定规范,建筑水泥的存放期通常为()个月。

A.1

B.2

C.3

D.6

题型:选择题

用乙醇沉淀溶于SDS的RNA时,可使用的盐类为()。

A.乙酸铵

B.乙酸钠

C.氯化锂

D.氯化钠

E.以上都可以

题型:选择题

高尔夫的英文单词四个字母分别表示G(Green)—绿色;O(Oxygen)—氧气;L(Light)—阳光F表示什么?()

A.F(FA.mily)—家庭

B.F(Full)—充满

C.F(Form)—正式

D.F(Foot)—步履。

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