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56. A. ideas　　　　　　　　　　 B. ambitions　　　　　　　　 C. achievement　　 　　 D. technique

55. A. presented　　　　　　　 B. marked　　　　　　　　　 C. lit　　　　　　　　　　　　　 D. associated

54. A. familiar　　　　　　　　 B. unrelated　　　　　　　　 C. creative　　　　　　　　　 D. imaginary

53. A. skillfully　　　　　　　　 B. routinely　　　　　　　　 C. vividly　　　　　　　　　　 D. deeply

52. A. equipped　　　　　　　 B. compared　　　　　　　 C. covered　　　　　　　　　 D. connected

51. A. put up with　　　　　 B. catch up with　　　　　 C. make use of　　　　　　 D. keep track of

Passage 1

(09·上海)

Most people believe they don’t have much imagination. They are 　　50　 .Everyone has imagination, but most of us, once we become adults, forget how to 　　51　 it. Creativity isn’t always　 52　 with great works of art or ideas. People at work and in their free time　 53　 think of creative ways to solve problems. Maybe you have a goal to achieve, a tricky question to answer or you just want to expand your mind! Here are three techniques to help you.

Making connections This technique involves taking　 54　 ideas and trying to find links between them. First, think about the problem you have to solve or the job you need to do. Then find an image, word, idea or object, for example, a candle. Write down all the idea/words　 55 　with candles: light, fire, matches, wax, night, silence, etc. Think of as many as you can. The next stage is to relate the　 56　 to the job you have to do. So imagine you want to but a friend an original　 57　 ; you could buy him tickets to match or take him out for the night.

NO limits! Imagine that normal limitations don’t　 58　 . You have as much time/space/money, etc. as you want. Think about your goal and the new　 59　 .If your goal is to learn to ski,　 60　 , you can now practise skiing every day of your life (because you have the time and the money). Now 　　61　 　this to reality.　 Maybe you can practise skiing ever day in December, or every Monday in January.

Be someone else! Look at the situation from a 　　62　 point of view. Good businessmen use this technique in trade, and so do writes. Fiction writers often imagine they are the　 63　 in their books. They ask question: What does this character want? Why can’t she get it? What changes must she make to get what she wants? If your goal involves other people, put yourself in their 　　64　 . The best fishermen think like fish!

50. A. wrong　　　　　　　　　 B. unbelievable　　　　　　 C. reasonable　　　　　　　 D. realistic

10．如圖所示，電阻不計(jì)的平行金屬導(dǎo)軌MN和OP水平放置，MO間接有阻值為R的電阻，導(dǎo)軌相距為d，其間有豎直向下的勻強(qiáng)磁場，磁感強(qiáng)度為B．質(zhì)量為m、電阻為r的導(dǎo)體棒CD垂直于導(dǎo)軌放置，并接觸良好．用平行于MN的恒力F向右拉動(dòng)CD，CD受恒定的摩擦阻力．f，已知F>f．問：

　(1)CD運(yùn)動(dòng)的最大速度是多少?

　(2)當(dāng)CD達(dá)到最大速度后，電阻R消耗的電功率是多少?

(3)當(dāng)CD的速度是最大速度的1/3時(shí)，CD的加速度是多少?

解析：(1)以金屬棒為研究對(duì)象，當(dāng)CD受力：F=F_A+f時(shí)，CD速度最大，

即：

(2)CD棒產(chǎn)生的感應(yīng)電動(dòng)勢為：

回路中產(chǎn)生的感應(yīng)電流為：

則R中消耗的電功率為：

(3)當(dāng)CD速度為最大速度的1/3即時(shí)，CD中的電流為最大值的1/3即則CD棒所受的安培力為：

　CD棒的加速度為：

9、如圖所示，兩根足夠長的直金屬導(dǎo)軌MN、PQ平行放置在傾角為θ的絕緣斜面上，兩導(dǎo)軌間距為L，M、P兩點(diǎn)間接有阻值為R的電阻．一根質(zhì)量為m的均勻直金屬桿ab放在兩導(dǎo)軌上，并與導(dǎo)軌垂直整套裝置處于磁感應(yīng)強(qiáng)度為B的勻強(qiáng)磁場中，磁場方向垂直斜面向下，導(dǎo)軌和金屬桿的電阻可忽略·讓ab桿沿導(dǎo)軌由靜止開始下滑，導(dǎo)軌和金屬桿接觸良好，不計(jì)它們之間的摩擦．

　　 (1)由b向a方向看到的裝置如圖1 5-2所示，請(qǐng)?jiān)诖藞D中畫出ab桿下滑過程中某時(shí)刻的受力示意圖；

　　 (2)在加速下滑過程中，當(dāng)桿ab的速度大小為v時(shí)，求此時(shí)ab桿中的電流及其加速度的大小；

　　 (3)求在下滑過程中，ab桿可以達(dá)到的速度最大值．

解：(1)重力mg，豎直向下；支撐力N，，垂直斜面向上；安培力F，沿斜面向上．

(2)當(dāng)ab桿速度為v時(shí)，感應(yīng)電動(dòng)勢E=BLv，此時(shí)電路電流

桿受到安培力

根據(jù)牛頓運(yùn)動(dòng)定律，有：　　　　

(3)當(dāng)時(shí)，ab桿達(dá)到最大速度

8、水平面上兩根足夠長的金屬導(dǎo)軌平行固定放置，間距為L，一端通過導(dǎo)線與阻值為R的電阻連接；導(dǎo)軌上放一質(zhì)量為m的金屬桿(見圖)，金屬桿與導(dǎo)軌的電阻不計(jì)；均勻磁場豎直向下．用與導(dǎo)軌平行的恒定力F作用在金屬桿上，桿最終將做勻速運(yùn)動(dòng)．當(dāng)改拉力的大小時(shí)，相對(duì)應(yīng)的勻速運(yùn)動(dòng)速度v也會(huì)改變，v和F的關(guān)系如圖 (取重力加速度g=10m／s ²)

(1)金屬桿在勻速運(yùn)動(dòng)之前做作什么運(yùn)動(dòng)?

(2)若m＝0.5 kg，L＝0.5 m，R＝0.5 Ω，磁感應(yīng)強(qiáng)度B為多大?

(3)由ν－F圖線的截距可求得什么物理量?其值為多少?

解： (1)變速運(yùn)動(dòng)(或變加速運(yùn)動(dòng)、加速度減小的加速運(yùn)動(dòng)，加速運(yùn)動(dòng))．

(2)感應(yīng)電動(dòng)勢E-vBL，感應(yīng)電流I=E/R

安培力

由圖可知金屬桿受拉力、安培力和阻力作用，勻速時(shí)合力為零

由圖線可以得到直線的斜率k=2

(3)由直線的截距可以求得金屬桿受到的阻力f，　　　 f=2(N)．

若金屬桿受到的阻力僅為動(dòng)摩擦力，由截距可求得動(dòng)摩擦因數(shù)　　μ=0.4