如图所示,在光滑水平面上,有一质量m1=0.30kg的小球A处于静止状态,现有一

题型:问答题

问题:

如图所示,在光滑水平面上,有一质量m1=0.30kg的小球A处于静止状态,现有一质量m2=0.20kg的小球B沿水平面以v0=10m/s的速度与小球A发生对心正碰,碰后两小球立即合为一个整体在光滑水平面上运动.求:

(1)碰撞前,小球B的动量大小;

(2)两小球碰撞后它们共同运动的速度大小.

考点:动量守恒定律
题型:问答题

患者心下痞满,恶心呕吐,肠鸣,便溏,舌质稍淡,舌苔淡黄而厚腻,脉滑,治宜()

A.生姜泻心汤

B.大黄黄连泻心汤

C.五苓散

D.半夏泻心汤

E.桂枝人参汤

题型:问答题

In one sense, we can trace all the problems of the American city back (91) a single starting point: we Americans don’t like our cities very much.
That is, on the (92) of it, absurd. After all, more than three-fourths of us now live in cities, and more are (93) to them every year. We are told that the problems of our cities are (94) more attention in Washington, and scholarship has discovered a whole new (95) in urban studies.
(96) , it is historically true: in the American psychology, the city has been a basically suspect institution, (97) with the corruption of Europe, totally lacking that sense of spaciousness and innocence of the (98) and the rural landscape.
I don’t pretend to be a scholar on the history of the city in American life. But my thirteen years in public (99) , first as an officer of the U. S. Department of Justice, then as Congressman, and now as Mayor of the biggest city in America have taught me (100) too well the fact that a p antiurban attitude (101) consistently through the mainstream of American thinking. Much of the (102) behind the settlement of America was in reaction (103) the conditions in European industrial centers and much of the theory (104) the basis of freedom in America was linked directly to the availability of land and the perfectibility of man outside the corrupt influences of the city.
What has this to do with the predicament of the modern city I think it has (105) to do with it. For the fact is that the United States (106) the federal government, which has historically established our national priorities, has simply never thought that the American city was "worthy" of (107) —at least not to the (108) of expending any basic resources on it.
Antipathy to the city predates the American experience. When industrialization (109) the European working man into the major cities of the continent, books and pamphlets appeared (110) the city as a source of crime, corruption, filth, disease, vice, licentiousness, subversion, and high prices.

A.all

B.only

C.but

D.one

题型:问答题

老年患者,反复咳嗽、咳痰10多年,近2年气促明显,活动后加重。就诊当天上午上厕所时突感气促加重,伴胸痛。体格检查,双肺呼吸音减弱,叩诊呈过清音,左上肺似呈鼓音。急诊检查首选下列哪项()。

A.胸部透视

B.心电图

C.血气分析

D.肺功能检查

E.血常规

题型:问答题

革兰阳性杆菌,有氧不生长,菌体排列呈Y、V等多形性,标本有醋酸味,最可能的细菌是()

A.破伤风杆菌

B.双歧杆菌

C.丙酸杆菌

D.艰难梭菌

E.白喉棒状杆菌

题型:问答题

用人单位瞒报工资总额的,由劳动保障部门责令改正,并处瞒报工资数额()的罚款。

A.1倍以上3倍以下

B.3倍以上5倍以下

C.5倍以上7倍以下

D.7倍以上9倍以下

更多题库