如图所示,在光滑的水平面上放着两块长度相等,质量分别为M1和M2的木板,在两木板

题型:选择题

问题:

如图所示,在光滑的水平面上放着两块长度相等,质量分别为M1和M2的木板,在两木板的左端分别放有一个大小、形状、质量完全相同的物块.开始都处于静止状态,现分别对两物块施加水平恒力F1F2,当物块与木板分离后,两木板的速度分别为V1和V2.若已知v1>v2,且物块与木板之间的动摩擦因数相同,需要同时满足的条件是(  )

A.F1=F2,且M1>M2

B.F1=F2,且Ml=M2

C.F1>F2,且M1=M2

D.F1<F2,且M1=M2

考点:牛顿第二定律
题型:选择题

阅读材料,回答问题。

材料一:抽水蓄能电站是既能抽水又能发电的水电站。它具有上、下水库。充分利用电力系统中某时段多余的电能,把下水库的水抽到上水库内,以势能的形式蓄能,电力系统需要时再从上水库放水至下水库进行发电。

材料二:抽水蓄能电站平面示意图

材料三:北京市电力自负荷构成图

(1)图中等高线的数值关系是:a_______b_________c_______d(填大于、小于或等于)。

(2)抽水蓄能电站发电厂房所在位置可能是甲、乙、丙、丁四处中的_______处,比较分析其原因。

 ___________________________________________________________________________________________

(3)抽水蓄能电站主既是发电厂又是用户。若该电站属于北京市电网系统,根据材料三可知,该电站一天中用电和发电的时间与城市中的______________用电密切相关。抽水蓄能可以带来哪些综合效益?

___________________________________________________________________________________________

题型:选择题

下列说法正确的是[ ]

A.若两个角的和为180°,则必有一个角是钝角

B.平面上A,B两点间的距离是线段AB

C.若线段AC=BC,则点C是线段AB的中点

D.平面上有三点A,B,C,过其中两点的直线有三条或一条

题型:选择题

根据《关于开展建筑施工用钢管、扣件专项整治的通知》建质电[2003]35号,下面哪一项不是工作要求?()

A.建立安全检测制度

B.建立信息报送制度

C.加强各部门间的协作配合

D.严格执法,依法行政

题型:选择题

The European Union’s Barcelona summit, which ended on March 16th, was played out against the usual backdrop of noisy "anti-globalization" demonstrations and massive security. If nothing else, the demonstrations illustrated that economic liberalization in Europe--the meeting’s main topic--presents genuine political difficulties. Influential sections of public opinion continue to oppose anything that they imagine threatens "social Europe", the ideal of a cradle-to-grave welfare state.

In this climate of public opinion, it is not surprising that the outcome in Barcelona was modest. The totemic issue was opening up Europe’s energy markets. The French government has fought hard to preserve a protected market at home for its state-owned national champion, Electricite de France (EDF). At Barcelona it made a well-flagged tactical retreat. The summiteers concluded that from 2004 industrial users across Europe would be able to choose from competing energy suppliers, which should account for "at least" 60% of the market.

Since Europe’s energy market is worth 350 billion ( $ 309 billion) a year and affects just about every business, this is a breakthrough. But even the energy deal has disappointing aspects. Confining competition to business users makes it harder to show that economic liberalization is the friend rather than the foe of the ordinary person. It also allows EDF to keep its monopoly in the most profitable chunk of the French market.

In other areas, especially to do with Europe’s tough labor markets, the EU is actually going backwards. The summiteers declared that "disincentives against taking up jobs" should be removed; 20m jobs should be created within the EU by 2010. But only three days after a Barcelona jamboree, the European Commission endorsed a new law that would give all temporary-agency workers the same rights as full-timers within six weeks of getting their feet under the desk. Six out of 20 commissioners did, unusually, vote against the measure--a blatant piece of re-regulation--but the social affairs commissioner, Anna Diamantopoulou, was unrepentant, indeed triumphant. A dissatisfied liberaliser in the commission called the directive "an absolute disaster".

The summit’s other achievements are still more fragile. Europe’s leaders promised to increase spending on "research and development" from its current figure of 1.9% of GDP a year to 3%. But how will European politicians compel businesses to invest more in research Nobody seems to know. And the one big research project agreed on at Barcelona, the Galileo satellite-positioning system, which is supposed to cost 3.2 billion of public money, is of dubious commercial value, since the Europeans already enjoy free access to the Americans’ GPA system. Edward Bannerman, head of economics at the Centre for European Reform, a Blairite think-tank, calls Galileo "the common agricultural policy in space.\

We learn from the text that Edward Bannerman is probably()

A. an enthusiast in agricultural policy

B. a tough leader in social affairs

C. an doubter of spending on research

D. a pioneer in space exploration

题型:选择题

关于顾问式销售,下列说法错误的是:()。

A.导购与顾客建立的是长期的、持续的关系

B.比传统销售更加专业、更加科学

C.对所有的顾客都是一样的接待方式

D.以顾客的需求为导向

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