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如圖所示是傾角為45°的斜坡,在斜坡底端P點(diǎn)正上方某一位置Q處以速度v0水平向左拋出一個(gè)小球A,小球恰好能垂直落在斜坡上,運(yùn)動(dòng)時(shí)間為t1.小球B從同一點(diǎn)Q處自由下落,下落至P點(diǎn)的時(shí)間為t2.不計(jì)空氣阻力,則t1:t2=(    )                                                                                                                                      

                                                                                                               

    A.      1:2     B.       1:    C. 1:3       D. 1:

                                                                                                                                        

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2009年3月1日16時(shí)13分,“嫦娥一號”完成了“受控撞月”行動(dòng),探月一期工程完美落幕.本次“受控撞月”,“嫦娥一號”經(jīng)歷了從距月表100km的圓形軌道進(jìn)入橢圓軌道的過程,如圖所示,a為橢圓軌道的遠(yuǎn)月點(diǎn),b為橢圓軌道的近月點(diǎn),則下列說法正確的是(                           )                                                                                     

                                                                                                            

    A.  從a點(diǎn)到b點(diǎn)的過程中,“嫦娥一號”受到的月球引力減小

    B.  從a點(diǎn)到b點(diǎn)的過程中,月球引力對“嫦娥一號”做正功

    C.  從a點(diǎn)到b點(diǎn)的過程中,“嫦娥一號”飛行的線速度減小

    D.  從a點(diǎn)到b點(diǎn)的過程中,“嫦娥一號”飛行的角速度減小

                                                                                                                                        

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如圖是伽利略1604年做斜面實(shí)驗(yàn)時(shí)的一頁手稿照片,照片左上角的三列數(shù)據(jù)如下表.表中第二列是時(shí)間,第三列是物體沿斜面運(yùn)動(dòng)的距離,第一列是伽利略在分析實(shí)驗(yàn)數(shù)據(jù)時(shí)添加的.根據(jù)表中的數(shù)據(jù),伽利略可以得出的結(jié)論是(    )                                                                                                                                           

1        1        32

4        2        130

9        3        298

16      4        526

25      5        824

36      6        1192

49      7        1600

64      8        2104

                                                                                                             

    A.  物體具有慣性

    B.  斜面傾角一定時(shí),加速度與質(zhì)量無關(guān)

    C.  物體運(yùn)動(dòng)的距離與時(shí)間的平方成正比

    D.  物體運(yùn)動(dòng)的加速度與重力加速度成正比

                                                                                                                                         

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自由下落的物體,其動(dòng)能與位移的關(guān)系如圖所示.則圖中直線的斜率表示該物體的(  )                         

                                                                                                                   

    A. 質(zhì)量   B. 機(jī)械能

    C. 重力大小  D. 重力加速度大小

                                                                                                                                        

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如圖所示,一只半球形碗倒扣在水平桌面上處于靜止?fàn)顟B(tài),球的半徑為R,質(zhì)量為m的螞蟻只有在離桌面高度大于或等于時(shí),才能停在碗上,那么螞蟻和桌面的最大靜摩擦力為( )                                                

                                                                                                 

  A. 0.6mg   B.      0.8mg      C. 0.4mg     D. 0.75mg

                                                                                                                                        

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物體沿直線以恒定加速度運(yùn)動(dòng),它的位移x與時(shí)間t的關(guān)系是x=24t﹣6t2(x的單位是m,t的單位是s),則它的速度為零的時(shí)刻是(                                  )                                                                                     

    A.      s  B. 2s   C. 4s    D. 24s

                                                                                                                                        

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用如圖所示的計(jì)時(shí)裝置可以近似測出氣墊導(dǎo)軌上滑塊的瞬時(shí)速度.已知固定在滑塊上的遮光條的寬度為4.0mm,遮光條經(jīng)過光電門的遮光時(shí)間為0.040s.則滑塊經(jīng)過光電門位置時(shí)的速度大小為(                 )                     

                                                                                                              

  A.  0.10m/s     B. 100m/s   C. 4.0m/s    D. 0.40m/s

                                                                                                                                        

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質(zhì)量為M=2kg的小平板車C靜止在光滑水平面上,車的一端靜止著質(zhì)量為mA=2kg的物體A(可視為質(zhì)點(diǎn)),如圖所示,一顆質(zhì)量為mB=20g的子彈以600m/s的水平速度射穿A后,速度變?yōu)?00m/s,最后物體A靜止在車上,求:                                                                                                                           

(1)平板車最后的速度是多少?                                                                               

(2)整個(gè)系統(tǒng)損失的機(jī)械能是多少?                                                                        

                                                                               

                                                                                                                                 

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以下是有關(guān)近代物理內(nèi)容的若干描述正確的是:(                             )                     

    A.  盧瑟福通過α粒子散射實(shí)驗(yàn),提出了原子核式結(jié)構(gòu)學(xué)說

    B.  太陽輻射的能量主要來自太陽內(nèi)部的重核裂變

    C.  質(zhì)子、中子、α粒子的質(zhì)量分別是m1、m2、m3,質(zhì)子和中子結(jié)合成一個(gè)α粒子,釋放的能量是(2m1+2m2﹣m3)C2

    D.  康普頓效應(yīng)證明光具有波動(dòng)性特征

    E.  光電效應(yīng)實(shí)驗(yàn)證明了光具有粒子性

                                                                                                                                 

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機(jī)械橫波某時(shí)刻的波形圖如圖所示,波沿x軸正方向傳播,質(zhì)點(diǎn)p的坐標(biāo)x=0.32m.從此時(shí)刻開始計(jì)時(shí).                     

(1)若每間隔最小時(shí)間0.4s重復(fù)出現(xiàn)波形圖,求波速.                                           

(2)若p點(diǎn)經(jīng)0.4s第一次達(dá)到正向最大位移,求波速.                                           

(3)若p點(diǎn)經(jīng)0.4s到達(dá)平衡位置,求波速.                                                             

                                                                                          

                                                                                                                                 

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