6. The captain was always honest with us and never ____ to disappointment, even when the ship sank.
A. gave off B. gave way C. gave away D. gave up
5. Whoever ______ a new idea of how to work out the puzzle will be given a prize.
A. comes up B. comes along with C. comes out with D. comes up with
4. There is a request that the room _______ after being used.
A. be cleaned B. would be cleaned C. is cleaned D will be cleaned
3. What did she think of the play?
She said she _______
A. had never seen a better one
B. had never seen so better one
C. has never seen a so good one
D. has never seen such a good one
2. The final examination is coming up soon, it is time for us to ______ our studies.
A. get down to B. get out C. get back for D. get over
第一节:单项填空(共20小题;每小题0.5分,满分10分)
从A、B、C、D四个选项中,选出可以填入空白处的最佳选项,并在答题纸上将该选项标号涂黑。
1. Iraq has _____ too many wars, making people _______ a lot.
A. got through , pay B. looked through , face
C. gone through suffer D. passed through destroy
18..
16. 解:(1)电动机消耗的电功率为 P电=UI=5.5×110W=550W
(2)绳对重物做功的机械功率为P机=mgv=45×10×0.70W=315W
(3) 电动机输出的电功率为P机出==W=450W
电动机线圈的电阻R的发热功率为 P电--P机出=100W
由 得
电动机线圈的电阻R=
17 (1)
③(2分)
(2) s=4.5m
18、质量m=5×10-6kg的带电粒子以v0=2m/s的速度从水平放置的平行金属板A、B中央水平飞人板间,如右图所示,已知板长L=10cm,板间距离d =2cm,当UAB=1000V时,带电粒子恰好沿直线穿过板间,则:
(1)该粒子带什么电?电荷量是多少?
(2)当板间电压在什么范围内时,此带电粒子能从板间飞出?
16.如图所示是利用电动机提升重物的示意图,其中D是直流电动机.p是一个质量为m的重物,它用细绳拴在电动机的轴上.闭合开关s,重物p以速度v匀速上升,这时电流表和电压表的示数分别是I=5.0A和U=110V,重物p上升的速度v=0.70m/s.已知该装置机械部分的机械效率为70%,重物的质量m=45kg(g取10m/s2).求(1)电动机消耗的电功率P电;(2)绳对重物做功的机械功率P机;(3)电动机线圈的电阻R.
17如图所示,水平地面上方分布着水平向右的匀强电场。一“L”形的绝缘硬质管竖直固定在匀强电场中。管的水平部分长为l1=0.2m,管的水平部分离水平地面的距离为h=5.0m,竖直部分长为l2=0.1m。一带正电的小球从管口A由静止释放,小球与管间摩擦不计且小球通过管的弯曲部分(长度极短可不计)时没有能量损失,小球在电场中受到的电场力大小为重力的一半。(g=10m/s2)求:(1)小球运动到管口B时的速度vB的大小; (2)小球着地点与管口B的水平距离s。]
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