试题与答案

(1)用落体法研究机械能守恒定律的实验中,某同学按照正确的操作选得纸带,但在处理

题型:问答题

题目:

(1)用落体法研究机械能守恒定律的实验中,某同学按照正确的操作选得纸带,但在处理纸带的过程中不小心把纸带撕成三个小段,并丢失了中间段的纸带,剩下的两段纸带如图所示.已知电源的频率为50Hz,在纸带上打出的各点间距离记录在下图中.

①A、B两点间的平均速度是______m/s;

②丢失的中间段纸带上有______个点;

③由这两段纸带可以求得当地的重力加速度g=______m/s2

(2).有一个额定电压为2.8V,功率约为0.8W的小灯泡,现要用伏安法描绘这个灯泡的I-U图线,有下列器材供选用:

A.电压表(0~3V,内阻6kΩ)

B.电压表(0~15V,内阻30kΩ)

C.电流表(0~3A,内阻0.1Ω)

D.电流表(0~0.6A,内阻0.5Ω)

E.滑动变阻器(10Ω,2A)

F.滑动变阻器(200Ω,0.5A)

G.蓄电池(电动势6V,内阻不计)

①用如图所示的电路进行测量,电压表应选用______,电流表应选用______.滑动变阻器应选用______.(用序号字母表示)

②通过实验测得此灯泡的伏安特性曲线如图所示.由图线可求得此灯泡在正常工作时的电阻为______Ω.

③若将此灯泡与电动势6V、内阻不计的电源相连,要使灯泡正常发光,需串联一个阻值为______Ω的电阻.

答案:

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题型:完形填空

There is an old saying about volunteer work that goes like this: "No one can do everything, but everyone can do something."

Today, many people volunteer their time and energy to help others. There are a lot of ways to meet other people's needs, and it seems there is a volunteer group for everything. Some provide education, while others offer adventure. Many do both. For example, some volunteers provide emergency help after a catastrophic event or disaster. Others are happy to get dirty while repairing homes or planting trees or flowers in poor neighborhoods. Young people see suffering and loneliness around them and find ways to help. And history lovers help archeologists search for ancient objects to help deepen knowledge of the past.

The volunteers also work in many areas around the world, including Haiti. More than two years have passed since a seven point zero earthquake shook the nation. The exact number of people who died may never be known. Estimates gave numbers from ninety five thousand to more than three hundred thousand.

Thousands of survivors of the Haitian earthquake still live in temporary shelters. Last year, former American President Jimmy Carter and his wife Rosalynn joined five hundred Habitat volunteers in the town of Leogane to build houses.

Organizations do not have to be large to get volunteers. An activist group in Dharamsala, India is a good example. Jodie Underhill from England arrived in northern India several years ago. She planned to volunteer for an environmental project. She found a lot to do there. She could hardly believe how much garbage was ruining some of the area's most beautiful sights. Miss Underhill learned about _______________________ while taking part in other volunteer projects. But soon enough she formed her own group, Mountain Cleaners. Miss Underhill says the work is very hard and the Indian media started calling her "Garbage Girl." But she says she was pleased with the name.

小题1:What does the passage mainly talk about? (no more than 8 words)

_____________________________________________________________

小题2:What does the underlined word “both” (Line 3, paragraph 2) probably refer to? (no more than 3 words)

_____________________________________________________________

小题3:What did former American President Jimmy Carter do as a volunteer? (no more than 8 words)

_____________________________________________________________

小题4:Fill in the blank in paragraph 4 with proper words. (no more than 5 words)

Miss Underhill learned about __________________ while taking part in other volunteer projects.

小题5:What kind of volunteer jobs do you want to join? And why? (no more than 20 words)

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