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【题目】(5分)在半径R=5 000 km的某星球表面,宇航员做了如下实验,实验装置如图甲所示,竖直平面内的光滑轨道由轨道AB和圆弧轨道BC组成,将质量m=0.2 kg的小球从轨道AB上高H处的某点静止滑下,用力传感器测出小球经过C点时对轨道的压力F,改变H的大小,可测出相应F的大小,F随H的变化如图乙所示。求:
(1)圆轨道的半径。
(2)该星球的第一宇宙速度。
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【题目】 ——Do you think we can get there on time?
——__________ the car doesn’t break down.
A. So long as B. Even though
C. As soon as D. As if
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【题目】How much ______the new dress ______you?
A. did; pay B. was; spend
C. was; take D. did; cost
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【题目】 I didn’t say I like it. ________I was very much against it.
A. At the same time B. Rather than
C. On the whole D. On the contrary
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【题目】冥王星与其附近的另一星体卡戎可视为双星系统。质量比约为7:1,同时绕它们连线上某点O做匀速圆周运动。由此可知,冥王星绕O点运动的
A.轨道半径约为卡戎的
B.角速度大小约为卡戎的
C.线速度大小约为卡戎的7倍
D.向心力大小约为卡戎的7倍
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【题目】She's such a quarrelsome woman. I don't know how you can ______ her.
A. put up B. put up with
C. stand up with D. stand with
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【题目】 It was when I got back to my apartment ______ I first came across my new neighbors.
A. who B. where C. which D. that
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【题目】When___for his views about his teaching job,Philip said he found it very interesting and rewarding
A.asking
B.asked
C.having asked
D.to be asked
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【题目】With the changes in the world’s climate, dinosaurs died, but many smaller animals lived on. It was the of
the fittest.
A. survival B. distinction
C. existence D. appearance
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【题目】下图为局部地区经纬网图。图中A点位于南纬70°,AB为晨昏线的一段;此刻,北京处于白昼;近期,C地日出时刻越来越早。读图回答下列各题。
【1】
A. 10点 B. 8点 C. 17点 D. 15点
【2】
A. 该日,大约在12月中旬
B. 该日,C地从西北方向日落
C. 该季节,珠江正值枯水期
D. 该季节,澳大利亚白昼比中国长
【3】
A. 东北 B. 东南 C. 西南 D. 西北
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