某次“验证机械能守恒定律”的实验中,用6V、50Hz的电磁打点计时器打出的一条纸

题型:实验题

问题:

某次“验证机械能守恒定律”的实验中,用6V、50Hz的电磁打点计时器打出的一条纸带如图5所示,O点为重锤下落的起点,每隔一个点选取一个计数点,分别记为A、B、C、D,各计数点到O点的长度已在图上标出,单位为毫米,重力加速度取10m/s2,若重锤质量为1kg。则:打点计时器打出B点时,重锤下落的速度=              m/s,

重锤增加的动能为               J。( 注:结果均保留3位有效数字 )

考点:实验:探究弹力与弹簧伸长的关系实验:探究小车速度随时间变化的规律实验:探究加速度与力、质量的关系实验:探究功与速度变化的关系
题型:实验题

农户联保贷款期限由贷款人根据借款人生产经营活动的周期确定,原则上不得超过一年(不得超过联保协议的期限,一般为3或5年)。( )

题型:实验题

—______are you going to stay there?     

—______a week.      [ ]

A. When; About          

B. How; For       

C. How long; For        

D. What; About  

题型:实验题
完型填空(共20小题;每小题1.5分,满分30分)
阅读下面短文,从短文后各题所给的四个选项(A、B、C和D)中选出可以填入空白处的最佳选项。 
For long, a little boy was wondering why his deskmate could rank 1st in the class whenever he wanted to, while he himself failed to: he only ranked 21st.
At home, he asked his Mom, “Mom, am I more   21 than others? I feel I am obedient and as careful as him, but   22 I always fall behind? ” Hearing the words, Mom was aware that her son began to  23  the sense of self-respect, which was now being injured by the ranking system.  24  at him, she went wordless, not knowing  25  to explain.
In another test, the son ranked 17th, while his deskmate remained 1st. Back home he   26  the same question. Mom really wanted to inform his son that   27  differs, which means that students ranking 1st are supposed to be cleverer than normal ones.  28 , was this discouraging answer the one that her son was constantly  29  about? Thank goodness she did not open her mouth.
How to answer her son’s question? There were times when she felt an urge to say, “You are too lazy. You are not as hard-working as others…”but she stopped   30  imagining her son suffering from the pains of unsatisfied grades and rankings. She thought it   31  to put any additional burden on his son and was trying to find out a perfect answer.
Time passing swiftly, the son   32  primary school. Despite studying harder and better, he was still unable to keep up with his deskmate. To show her pride of him, Mom decided to   33  him to the sea. During the trip, she managed to give an answer.
Now, the son no longer worries about his   34 , and there are no boring guys who would inquire his grades in primary school, because,   35  the 1st ranking, he is admitted to Tsinghua University. Back home in winter vacation, he was invited to   36 the students and parents in his high school, In the speech, he mentioned a valuable experience in his childhood, “…When my mother and I were lying on the   37 , she pointed to the front and said, “Do you see the seabirds struggling for food over there ?When the waves come near, little birds can rise   38 while awkward seagulls would take more time to complete the process. However, have you noticed birds that finally fly  39 the endless ocean are none other than the awkward seagulls?” The speech   40  many mothers present to tears, including his mother.
小题1:
A.considerateB.carelessC.stupidD.clever
小题2:
A.what ifB.how comeC.how aboutD.what for
小题3:
A.loseB.haveC.winD.beat
小题4:
A.ShoutingB.GlaringC.StaringD.Pointing
小题5:
A.whichB.whyC.whenD.how
小题6:
A.raisedB.metC.answeredD.got
小题7:
A.intelligenceB.rightC.knowledgeD.strength
小题8:
A.ThereforeB.StillC.ThusD.However
小题9:
A.enthusiasticB.curiousC.crazyD.clear
小题10:
A.ifB.beforeC.unlessD.when
小题11:
A.cruelB.importantC.disappointedD.necessary
小题12:
A.attendedB.startedC.finishedD.entered
小题13:
A.guideB.takeC.bringD.push
小题14:
A.homeworkB.belongingsC.healthD.rankings
小题15:
A.inB.byC.withD.on
小题16:
A.teachB.deliverC.addressD.face
小题17:
A.floorB.roadC.bankD.beach
小题18:
A.quicklyB.suddenlyC.slowlyD.sharply
小题19:
A.intoB.throughC.acrossD.throughout
小题20:
A.madeB.movedC.impressedD.inspired
题型:实验题

看下图回答问题。

(1)上图是阿拉伯数字,5个空格所代表的数字依次是___________________   

(2)这些数字是由谁发明的?又是怎样传到西方的?

_____________________________________________________

题型:实验题

视窗环境是一种面向( )的命令接口。

A.键盘

B.屏幕

C.扫描仪

D.鼠标

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