问题 选择题

已知地球半径为R,质量为M,自转角速度为( ,万有引力恒量为G,地球同步卫星距地面高度为h,则(  )

A.地面赤道上物体随地球自转运动的线速度为(R

B.地球同步卫星的运行速度为(h

C.地球近地卫星做匀速圆周运动的线速度为

D.地球近地卫星做匀速圆周运动的周期大于

答案

AC

题目分析:地面赤道上物体随地球自转的角速度等于地球自转的加速度,半径等于地球半径R,根据可求地面赤道上物体随地球自转运动的线速度为(R,所以A正确;地球同步卫星的轨道半径为R+h,所以其线速度为,所以B错误;地球近地卫星的线速度,根据可求,所以C正确;,得,所以地球近地卫星的角速度大于同步卫星的角速度,故也大于地球自转的角速度,再根据可知,地球近地卫星做匀速圆周运动的周期小于,所以D错误。

材料分析题

读材料,回答下列问题。

材料一:

“我国土地利用类型的百分比示意图”

材料二:

    2001年的春季,在内蒙古中西部、甘肃、兰州出现了沙尘暴天气,近8年来,西北地区遭受沙尘暴袭击34次之多,直接经济损失20多亿,80%地区受灾。沙尘已成为全国性的新的环境杀手。北京、南京、天津、哈尔滨等东部城市也成为沙尘光顾的新地。扬沙、沙尘、沙尘暴天气形成的原因除自然因素外,北部过度放牧、垦荒、挖药材等,致使北方沙漠地区的植被以每年66万多公顷的速度锐减。

材料三:

    我国专家利用遥感技术得出结论:多年来对沙化土地总体上破坏大于治理,全国的沙化土地面积由50至60年代每年扩展2400平方千米,其中部分地区近年开垦的土地中,有近一半已撂荒,成为新的沙尘源头。

(1)从材料一可知我国土地资源的现实状况是________________________________________________。

(2)我国已利用土地资源中比重最大的是________,主要分布于________________________________,

林地主要分布于________。如今由于人为因素,地表植被遭到破坏,导致________恶化。因此,我们在

利用土地资源时,应坚持“________________________________”的基本国策。

(3)由资料二、三可知我国生态环境的基本状况是________________________________。为解决这些问

题,请依据可持续发展观点提出你的建议:_______________________________________。

阅读理解


What brings a nation together? Of the four choices — shared values, language, history, and religion, it’s shared values. In our latest poll (民意调査), seven out of 16 countries chose values as the greatest factor (因索)bringing a nation together, and six preferred language. Both choices scored high in the poll, suggesting that our values and how we express them are closely linked Still, history was not forgotten in some countries, particularly in Mexico and Russia. Even Canada and the United States chose national histories as the second-most important factor uniting their people. The biggest surprise? Not one country picked religion as its top choice.
Respect your elders
In most countries, the oldest
generation considered values more important to a nation than did those who are under 45 years old.
Do you speak Canadian?
Language scored lower in Canada than in all other countries polled, perhaps because the country speaks two official languages, French and English.
Church and state
Most people polled do not connect their religious beliefs to their national pride. Religion ranked last in 13 countries — with France scoring it at 1%, the lowest of all.
小题1:According to the poll, what was the most important factor in bringing a nation together?
A.Language.B.Values.C.History.D.Religion.
小题2:In which country did language score the lowest in their national pride?   
A.Canada.B.Mexico.C.France.D.America.
小题3:According to the charts, shared values and language were considered equally important in         .  
A.AustraliaB.BrazilC.ChinaD.India