问题 选择题

我国自行研制发射的“风云一号”“风云二号”气象卫星的飞行轨道是不同的,“风云一号”是极地圆形轨道卫星,其轨道平面与赤道平面垂直,周期为T1=12h;“风云二号”是同步卫星,其轨道平面就是赤道平面,周期为T2=24h,两颗卫星相比(  )

A.“风云一号”离地面较高

B.“风云一号”每个时刻可观察到的地球表面范围较大

C.“风云一号”线速度较大

D.若某时刻“风云一号”和“风云二号”正好同时在赤道上某个小岛的上空,那么再过12小时,它们又将同时到达该小岛的上空

答案

A、由万有引力提供向心力的周期表达式:G

Mm
r2
=m
4π2
T2
r,可知:r3=
GMT2
4π2
,风云一号周期12h,风云二号周期是24h,故风云二号离地面高,故A错误

B、风云一号有覆盖全球的观测范围,而风云二号,是相对地球静止的,其范围无法达到全球内,B错误

C、由A知,风云二号的半径大,由:G

Mm
r2
=m
v2
r
,得:v=
GM
r
,故风云一号线速度大,故C确

D、再过12h,“风云一号”卫星转了1轴,但地球仅仅转了半周,故D错误.

故选:C.

完形填空
At Life’s Crossroads
Leaving high school, I had to choose a career path—medicine or business—before college started in three months, but I couldn’t decide. Both my uncles suggested I work for a month in a         followed by a month in a hospital before I could know what to do. It seemed like a good idea.
Then near the end of two months, I began thinking about my two         . The bank had offered better working conditions. The hospital was full of excitement, but the training was hard. It seemed that the choices of        was going to run out.
The Last day of my work at the hospital, I was         home when I saw a boy hit by a bus and lie in the road as the bus run away.        stopped. I know if the boy stayed there, he would die very soon. So, without help, I lifted him into my car.
The next day, I went to see him. His family were sitting around his bed. The doctor introduced me as “the person who saved the boy’s life”.Everyone got up, with        smiles on their faces. The mother held my hands to her face, repeating again and again, “See, you are an angel!”
What a feeling this was, to help save the life of another person!         , I knew I wanted to do for the rest of my life. I went to college for my medical studies.
We may spend a lot of time wondering about what         to take in our lives, but sometimes you don’t really have to worry about your       decisions. They are made for you by some quality(品质) in you—by what you’re        to do when necessary.
小题1:
A.teamB.companyC.gardenD.laboratory
小题2:
A.unclesB.hobbiesC.colleges D.experiences
小题3:
A.businessB.educationC.careerD.subject
小题4:
A.runningB.ridingC.stayingD.driving
小题5:
A.All B.FewC.NobodyD.Someone
小题6:
A.gentleB.weak C.pleasant D.grateful
小题7:
A.LuckilyB.ProbablyC.ImmediatelyD.Quietly
小题8:
A.pathB.actionC.interest D.advice
小题9:
A.big B.personalC.quickD.fair
小题10:
A.freeB.afraidC.readyD.careful
问答题 简答题