试简述流体压强与流速的关系.如如图所示是飞机机翼模型,请简单解释飞机获得向上升力

题型:问答题

问题:

试简述流体压强与流速的关系.如如图所示是飞机机翼模型,请简单解释飞机获得向上升力的原因.

考点:飞机的升力
题型:问答题

1945年美国向日本的广岛和长崎投下原子弹,平民伤亡惨重。爱因斯坦认为“人类打开了这个潘多拉魔匣”。打开这个“潘多拉魔匣”的钥匙是  [ ]

A、牛顿经典力学    

B、相对论  

C、量子力学    

D、网络信息技术

题型:问答题

Many foreigners who have not visited Britain call all the inhabitants(居民) English, for they are used to thinking of the British Isles as England. In fact, the British Isles contain a variety of peoples and only the people of England call themselves English. The others refer to themselves as Welsh, Scottish, or Irish, as the case may be; they are often slightly annoyed(苦恼) at being classified as 'English'.

In Scotland the sound denoted by the letter 'R' is generally a strong sound, and 'R' is often pronounced in words in which it would be silent in southern English. In the Highlands and the Western Isles the ancient Scottish language, Gaelic, is still heard. The Scots are said to be a serious, cautious, thrifty(节约的) people, rather inventive(善于创造的) and somewhat mystical. All the Celtic peoples of Britain (the Welsh, the Irish, the Scots) are often described as being more 'fiery(暴躁的)' than the English. They are often of a race that is quite different from the English.

The Welsh have protected their language to a remarkable extent. The English generally look upon the Welsh as an emotional(易动感情的) people who are, however, somewhat difficult to get to know easily.

Ireland is divided into two parts. The six countries of Northern Ireland are still part of Great Britain, though, in normal circumstances(环境), they have their own Parliament. The Irish are known for their charm and vivacity(活泼), as well as for the beauty of the Irish girls. Irish, often calls Erse, is a form of Gaelic. It was in danger of dying out, but when the territory(地域) of the Republic became independent, Erse was received, and is now the official first language of the Republic, English being the second. The Irish are known for their charm and vivacity, as well as for the beauty of the Irish girls.

小题1:Why do many foreigners call the inhabitants English?

A.Because only English live on the British Isles.

B.Because only English plays a more important role than the others.

C.Because all the people are glad to be regarded as English.

D.Because they are used to thinking of the British Isles as England.小题2:Today we still can hear Gaelic--the ancient Scottish language in __________.

A.both England and Scotland

B.both Wales and Ireland

C.both Highland and Western Isles

D.both Northern Ireland and England小题3: According to the passage, which of the statements is TRUE?

A.“R” is often pronounced in words in which it would be silent in north English.

B.The Welsh, the Irish and the Scots are all the Celtic peoples of Britain.

C.The Celtic peoples are often of a race that is little different from the English.

D.The Welsh have not protected their language very carefully.小题4:Irish is a form of ________, and is now the official ______ language of the Republic.

A.English; first

B.Gaelic; second

C.Gaelic; first

D.English; second

题型:问答题

下列现象能说明分子之间存在引力的是    [ ]

A.磁铁能吸引大头针 

B.用丝绸摩擦过的玻璃棒能吸引轻小纸屑  

C.挂衣服的塑料吸盘压紧在玻璃上,很难被拉开  

D.两块表面磨平、干净的铅块,压紧后在它下面能挂较重的物体而不被拉开

题型:问答题

患者55岁,右下肢屈膝受限3个月。3个月前行髌骨骨折切开复位张力带内固定术,术后石膏外固定6周,自行锻炼。体格检查:右膝关节前弧形术痕,与膝部组织粘连明显,髌骨两侧压痛,膝关节活动范围10°~40°。右伸膝肌力3级,跛行。

该患者膝关节不宜选用的治疗方法为()。

A.关节牵引

B.步行训练

C.等速肌力训练

D.耐力训练

E.关节活动度训练

题型:问答题

风景名胜区应具备什么样的条件?

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