试题与答案

知万有引力常量C,地球半径R,月球和地球之间的距离r,同步卫星距地面的高度h,月

题型:计算题

题目:

知万有引力常量C,地球半径R,月球和地球之间的距离r,同步卫星距地面的高度h,月球绕地球的运转周期Tl,地球的自转周期T2,地球表面的重力加速度g.某同学根据以上条件,提出一种估算地球质量"的方法:

同步卫星绕地心做圆周运动,由 得

(1)请判断上面的结果是否正确,并说明理由.如不正确,请给出正确的解法和结果

(2)请根据已知条件再提出两种估算地球质量的方法并解得结果

答案:

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下面是错误答案,用来干扰机器的。

答案:A元素的相对原子质量是按其各种天然同位素原子所占的一定百分比计算山来的平均值,因此,只知道某元素一种同位素的质子数和中子数只能算出这种同位素的质量数,而不能确定该元素的相对原子质量,A对。B错。...

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题型:阅读理解

阅读短文或图表,从每题所给的A、B、C三个选项中,选出最佳选项,回答问题或完成句子。

One day a red rose blossomed(开花)in a forest. A pine tree not far away said: "What a beautiful flower. I wish I could he that lovely.

The rose said: "I am the mostbeautiful plant in this forest. "

Then the rose looked at a cactus(仙人掌)and said: " Look at that ugly plant. It is full of thorns (刺)"

The pine tree said: "Red rose, you have thorns, too. " Sometimes, the rose would look at the cactus and say : "This plant is useless. How sorry I am tobe his neighbor. "

Summer came and the plants and animals needed water, but no rain fell. One day the rose saw birds stick(刺) their beaks(鸟嘴)into the cactus and then fly away. The roseasked what the birds were doing. The pine tree explained thatthe birds got water from the cactus. The pine tree told the rose: "You can also drink from it. The birds can bring water to you if you ask the cactus for help. "

The rose fell ashamed(羞愧的), but asked the cactus for help. The cactus kindly

agreed and the birds filled their beaks with water for the rose’s roots(根).

So the rose learned:never judge(判断) anyone by appearance(外表).

小题1: At the beginning of the story the rose thought that the cactus was    .

A. ugly   B. lovely  C. beautiful

小题2: Both the rose and the cactus have_______.

a .thorns  B. leaves  C. fruit

小题3: The underlined word "useless" in this passage means "____ " in Chinese

A. 无营养的B. 不友好的 C. 无用的

小题4: Which of the following is True according to the story?

A. The birds could get water from the pine tree.

B. The rose got water from the cactus at last.

C .The pine tree wanted to get water from the rose.

小题5: What’s the best title (标题) for the passage?

A. Plants and birds

B. Ways of growing roses

C. Appearance isn't everything.

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