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问题 实验题

在进行“摩擦力的大小与什么因素有关？”的实验中，三次实验情况分别如图甲、乙、丙所示。（g取10N/kg）

（1）实验时，让木块在水平木板（或棉布）上做_____________ 运动，这时弹簧测力计的示数等于滑动摩擦力的大小。根据图示的情况将数据填入表格中；

（2）观察比较甲、乙两图，可得到的结论是：_________________________________ ；

（3）观察比较甲、丙两图，可得到的结论是：________________________________

答案

（1）匀速直线；压力依次为： 20； 36； 20； 摩擦力依次为：3.6； 6.6； 5.6

（2）粗糙程度相同时，压力越大，摩擦力越大

（3）压力相同时，接触面越粗糙，摩擦力越大

单项选择题

Why is (71) fun What delights may its practitioner expect as his reward First is the Sheer joy of making things．As the child delights in his mud pie，So the adult enjoys building things，especially things of hid own design．Second is the pleasure of making things that are useful to other people．Third is the fascination of fashioning complex puzzle-like Objects of interlocking moving parts and Watching them work in subtle cycles，playing out the consequences of principles built in from the beginning．Fourth is the joy of always learning， Which Springs from the (72) nature of the task．In one Way or another the problem id ever new, and its solver learns something：sometimes (73) ，sometimes theoretical，and sometimes both．Finally there is the delight of Working in such a tractable medium．The (74) ，like the poet，works only slightly removed from pure thought-stuff. Few media of creation are so flexible，so easy to polish and rework，so readily capable of realizing grand conceptual Structures． Yet the program (75) ，unlike the poet's words，is real in the sense that it moves and works，producing visible outputs separate from the construct itself．It prints results，draws pictures，produces sounds，moves arms．Programming then is fun because it gratifies creative longings built deep Within us and delights sensibilities we have in common With all men．

（72）处填（）。

A．repeating

B．basic

C．non-repeating

D．advance
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单项选择题

缺铁性贫血，经铁剂治疗后1周，首先出现的治疗反应是

A．红细胞数升高

B．红细胞比积增加

C．血小板增加

D．网织红细胞增加

E．细胞平均容积(MC恢复正常
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