如图所示，一辆小车静止在水平地面上，bc是固定在小车上的水平横_爱下问搜题

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问题选择题

如图所示，一辆小车静止在水平地面上，bc是固定在小车上的水平横杆，物块M穿在杆上，M通过细线悬吊着小物体m，m在小车的水平底板上，小车未动时细线恰好在竖直方向上．现使小车向右运动，全过程中M始终未相对杆bc移动，M、m与小车保持相对静止，已知a₁∶a₂∶a₃∶a₄＝1∶2∶4∶8，M受到的摩擦力大小依次为Ff₁、Ff₂、Ff₃、Ff₄，则以下结论正确的是(　　)．

A．Ff₁∶Ff₂＝1∶2

B．Ff₂∶Ff₃＝1∶2

C．Ff₃∶Ff₄＝1∶2

D．tanα＝2tanθ

答案

ACD

题目分析：甲乙两图中，M水平方向只受静摩擦力作用，根据牛顿第二定律得：f₁=Ma₁f₂=Ma₂而a₁：a₂=1：2，则f₁：f₂=1：2，故A正确，B错误；丙丁两图中，对m和M整体受力分析，受总重力（M+m）g、支持力N、摩擦力f，如图

根据牛顿第二定律，有f=（M+m）a 所以f₃：f₄=a₃：a₄=4：8=1：2，故C正确，D错误；对m受力分析，受重力和绳的拉力（T），则Tsinω＝ma,Tcosω＝mg,得，D正确；由以上分析得：,B错误。

单项选择题 A型题

“实喘者有邪，邪气实也；虚喘者无邪，元气虚也”一语出自（）

A.《金匮要略》

B.《景岳全书》

C.《丹溪心法》

D.《类证治裁》

E.《医门法律》

完形填空

Mr. Glen is a millionaire. Five years ago, after returning from abroad to his motherland, he ___36___his small company. Speaking of success, Glen often tells us a story about his extra expensive “school” fee. He always ___37___his success to it.
At that time, Glen, who already got a Ph.D. degree, ___38___to return to the homeland, starting a company. Before leaving, he bought a Rolex watch with the ___39___made through years of work after school and the scholarships. At the airport he had to accept the ___40___customs check. The watch on his wrist was also demanded to be taken down for ___41___. Glen knew that carrying the specific goods out had to pay the tax, and he worried about paying ___42___for his watch. So when he was checked, he told a lie that his watch was a ___43___fake（假货）. When he was ___44___of his “smarts”, immediately, in the presence of Glen, the officers hit the watch, ___45___cost nearly 100,000 into pieces ___46___hearing Glen’s words. Glen was ___47___. Before he understood why, he was taken to the office to be examined ___48___. For many times of entry-exit ___49___he knew that only those people in the “blacklist” would “enjoy” this special treatment. The officers looked over everything carefully in the box, and ___50___him no matter what time of entry and exit he must accept the check and if __51___reusing and carrying fake and shoddy goods, he would be ___52 __according to law! Suddenly, his face turned red, and he had nothing in mind after boarding the plane for long.
After returning to the homeland, he often told the story to his family, and his employees, too. He said that this made a deep ___53___on him, because the additional high “school” fee that he had ever paid made him realize the value of ___54__, which he would remember as the ___55___of his success forever.

A．Disappointed

B．experiences

C．experiments