作用于一个物体上的两个共点力,大小分别为20N、30N,则它们的合力大小可能是(

题型:选择题

问题:

作用于一个物体上的两个共点力,大小分别为20N、30N,则它们的合力大小可能是(  )

A.60N

B.28N

C.8N

D.5N

考点:力的合成
题型:选择题

Fear seems to be the dominant mood of the moment. Hurricanes, tidal waves, floods, earthquakes and terrorism this year have all brought with them not only appalling scenes of devastation, death and suffering, but also outrage at the lack of preparations to avoid or cope with these disasters. Now even the birds of the air are a threat, we are told. That migrating flock visible On the horizon at sunset, once a consoling reminder of the eternal rhythms of nature, could be carrying the virus which might soon kill tens of millions of people.

Given the many fingers pointed at governments in the wake of other disasters this year, it is hardly surprising that they are scrambling to respond to the threat posed by avian influenza. After confirmation this week that the HSN1 strain of bird flu, which has been spreading quickly in Asia, had been discovered in Romania and perhaps Greece, European Union foreign ministers convened an emergency meeting. President George Bush, still smarting from a torrent of criticism of his government’s clumsy response to Hurricane Katrina, has promised to rush out emergency plans for dealing with an outbreak of pandemic flu which have been stalled for years. Countries around the world are hurrying to stockpile the only current antiviral drug, Tamifln, which might be effective in saving lives in any pandemic or curbing its spread. The World Health Organisation is calling for an internationally coordinated effort. Health ministers from around the globe are due to meet next week in Canada to discuss what steps to take.

Is any of this eff6rt justified Or are politicians simply helping to feed public panic, and then covering themselves by promising to spend lavishly against a threat which may never materialize and to reduce a risk which they do not understand To ask these questions is not to counsel complacency, but to apply the kind of test which is required in any kind of disaster planning, not least because the world is an inherently dangerous place and it is impossible to plan against every possible disaster. With the media full of warnings of impending mass death, an overreaction is all too possible.

The phrase "not least" in the last but one sentence of the text means ()

A. at most

B. not at all

C. marginally

D.particularly

题型:选择题

福莱特认为,解决社会冲突主要有三个途径,这三个途径不包括( )

A.一方占据上风

B.互相妥协

C.摩擦

D.整合

题型:选择题

女性,49岁,近半年数次发作性右上腹疼痛,恶心呕吐,多为夜间睡眠后发作,并向右肩部放射。检查:肥胖体质,BP110/90mmHg,P90次/分,右上腹轻度压痛,无腹肌紧张。

虽经治疗未缓解,反而持续性疼痛加重,右上腹压痛,反跳痛,腹肌紧张,体温38.5℃,此时可能的诊断()。

A.急性坏死性胰腺炎

B.十二指肠溃疡穿孔并弥漫性腹膜炎

C.胆总管结石

D.结石性急性坏疽性胆囊炎

E.急性化脓性胆管炎

题型:选择题

你船是一艘限于吃水的船舶在航道水深有限的水域中航行,看见左舷驶近的一艘悬挂有球、菱形、球号型的来船与你船航向交叉,并构成碰撞危险,则:()

A.你船应给他船让路

B.他船应给你船让路

C.他船不应妨碍你船的航行,但你船仍应给他船让路

D.他船不应妨碍你船的航行,你船应等待他船采取行动为你船留出足够的水域安全通过

题型:选择题

全自动车钩与半自动车钩结构上的区别包括()。i解钩气缸ii电钩头ⅲ机械钩头iv对中装置

A、i&ii

B、i&iii

C、i&iv

D、ii&iii

更多题库