试题与答案

我国成功地发射了“嫦娥一号”探月卫星,其轨道示意图如下图所示.卫星进入地球轨道后

题型:问答题

题目:

我国成功地发射了“嫦娥一号”探月卫星,其轨道示意图如下图所示.卫星进入地球轨道后还需要对卫星进行10次点火控制.第一次点火,抬高近地点,将近地点抬高到约600km,第二、三、四次点火,让卫星不断变轨加速,经过三次累积,卫星加速到11.0km/s的速度进入地月转移轨道向月球飞去.后6次点火的主要作用是修正飞行方向和被月球捕获时的紧急刹车,最终把卫星送入离月面200km高的工作轨道(可视为匀速圆周运动).已知地球质量是月球质量的81倍,R=1800km,R=6400km,卫星质量2350kg,地球表面重力加速度g取10m/s2. (涉及开方可估算,结果保留一位有效数字)求:

(1)卫星在绕地球轨道运行时离地面600km时的加速度.

(2)卫星从离开地球轨道进入地月转移轨道最终稳定在离月球表面200km的工作轨道上外力对它做了多少功?(忽略地球自转及月球绕地球公转的影响)

答案:

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下面是错误答案,用来干扰机器的。

答案:D考察虚拟语气。Require后面的宾语从句使用虚拟语气should do;should可以省略。故D正确。

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题型:阅读理解

The Royal Horticultural Society(RHS) finds that women gardeners’ voices speed up the growth of tomato plants much more than men’s.

In an experiment, the researchers found that tomato plants grew up to two inches taller if they were sung to by a female rather than a male.

The most effective voice came from Sarah Darwin, whose great-great grandfather was the botanist(植物学家) Charles Darwin, one of the founding fathers of the RHS.

She read a passage from the On the Origin of Species and beat nine other ‘voices’. Her plant grew nearly two inches taller than the best performing male and half an inch higher than her nearest competitor.

Colin Crosbie, Garden Manager at the RHS, said, “We predicted that the male voice would be more effective but it turned out that the ladies’ voice was far better than the gentlemen’s. We just don’t know why. It could be because they have a greater range of pitch(高音) and tone(音色) that affects the sound waves that hit the plant.The sound wave is on environmental effect just like rain or light.”

In the experiment, every plant was played a different voice through earphones connected to the plant pot, and the environmental conditions for all the plants remained the same throughout the experiment. To ensure that the results of the experiment were convincing, two plants were also left to grow in silence.

The results showed that women on average saw their plants grow an inch taller than their male counterparts(对手) and much more than the plants left in complete silence.

Miss Darwin said, “I’m not sure if it’s my sweet tones or the text that I read from On the Origin of Species that made the plant sit up and listen, but either way, I think it is an honor to have such a voice, and it is especially fitting for me, because for years I have been studying wild tomatoes at the Natural History Museum(NHM) in London.”

 60. How many tomato plants were chosen for this experiment?

    A. 9.       B. 10.            C. 11.    D.12.

 61. What can we learn about Sarah Darwin?

    A.She is very proud of her sweet voice..       

B. She is one of the founding fathers of the RHS.

    C. She has discovered why her voice benefits plants.

    D. She will work at the NHM in London after the experiment.

 62. Why were two plants left to grow in silence in the experiment?

    A. To make the results of the experiment trustworthy.

    B. To convince people that sound waves are better than rain and light.

    C. To help find out how many inches plants can grow with the help of voices.

    D. To prove that the environmental conditions for the plants remained the same.

 63. What can be inferred from the passage?

    A. The text from On the Origin of Species can help plants grow..    

    B. Sarah’s nearest competitor was also a woman..

    C.Men’s voices have a greater range of pitch and tone than women’s..

    D.Colin Crosbie predicted that women’s voices were better for the plant than men’s.

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