我们知道,在北半球地磁场的竖直分量向下。飞机在我国上空匀速巡航,机翼保持水平,飞

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问题:

我们知道,在北半球地磁场的竖直分量向下。飞机在我国上空匀速巡航,机翼保持水平,飞行高度不变。由于地磁场的作用,金属机翼上有电势差。设飞行员左方机翼末端处的电势为φ1,右方机翼末端处的电势为φ2

A若飞机从西向东飞,φ1比φ2高;

B、若飞机从东向西飞,φ2比φ1高;

C、若飞机从南向北飞,φ1比φ2高;

D、若飞机从北向南飞,φ2比φ1

考点:磁场对运动电荷的作用:洛伦兹力、左手定则
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关于浓度均为0.1mol/L的三种溶液:①氨水、②盐酸、③氯化铵溶液,下列说法不正确的是(  )

A.c(NH+4):③>①

B.水电离出的c(H+):②>①

C.①和②等体积混合的溶液:c(H+)=c(OH-)+c(NH3•H2O)

D.①和③等体积混合后的溶液:c(NH+4)>c(Cl-)>c(OH-)>c(H+

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下列各项哪个征象进入第二产程()

A.产妇屏气向下用力

B.产妇排尿困难

C.胎头部分露于 * *

D.宫口开全

E.脐带脱出于 * * 口外

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It is quite reasonable to blame traffic jams, the cost of" gas and the great speed of modern life, but manners on the toad are becoming horrible. Eye,body knows that the nicest men would become fierce tigers behind the wheel. It is all right to have a tiger in a cage, but to have one in the driver’s seat is another matter.
Road politeness is not only good manners, but good sense too. It takes the most cool-headed drivers great patience to give up the desire to beat back when forced to face rude driving. On the other hand, a little politeness goes a long way towards reducing the possibility of quarrelling and fighting. A friendly nod or a wave of thanks in answer to an act of politeness helps to create an atmosphere of good will and calmness so necessary in modern traffic conditions. But such behaviors of politeness are by no means enough. Many drivers nowadays don’t even seem able to recognize politeness when they see it.
However, misplaced politeness can also be dangerous. Typical examples are the driver who waves a child crossing the street at a wrong place into the path of oncoming cars that may be not able to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they want to.
An experienced driver, whose manners are faultless, told me it would help if drivers learnt to correctly join in traffic stream without causing total blockages that give rise to unpleasant feelings. Unfortunately, modern drivers can’t even learn to drive,let alone master the roadmanship. Years ago, experts warned us that the fast increase of the car ownership would demand more give-and-take from all road users. It is high time for all of us to take this message to heart.

Troubles on the road are often caused by______.

A. traffic jams



B. the behavior of the drivers
C. great speed



D. terrible road conditions

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本地交换网网管系统是本地网交换网络运行管理、业务提供及保障的重要手段。()

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通过锁骨中点的垂线称()。

A.腋中线

B.前正中线

C.锁骨中线

D.后正中线

E.脊柱旁线

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