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6.-Mike, what did our monitor say just now?

-Every boy and every girl as well as teachers who    to visit the museum asked to be at the school gate before 6:30 in the morning.

A. is; is                    B. are; is                    C. is; are              D. are; are

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5. Tom as well as two of his friends ________ to the concert last night A. has been invited                                     B. had been invited 

C. were invited                                        D. was invited

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4. A variety of books  _____________ the children of different ages.

A. are interested in                                    B. is interested in

C. are intending for                                    D. is intending for

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3. This special strain of rice ___________ one-third more of the crop in the same field.

A. makes possible to produce                           B. makes it possible to produce

C. make possible producing D. make it possible producing

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2. The rich_____ not always happy. .  

A. is                       B. are                       C. has                 D. have

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1. The teacher, with 6 girls and 8 boys of her class, _______ visiting a museum when the earthquake struck.  

A. was                    B. were                     C. had been           D. would be

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12.

图4-1-30

如图4-1-30所示,在距地面80 m高的水平面上做匀加速直线运动的飞机上每隔1 s依次放下abc三物体,抛出点abbc间距分别为45 m和55 m,分别落在水平地面上的ABC处.求:

(1)飞机飞行的加速度;

(2)刚放下b物体时飞机的速度大小;

(3)bc两物体落地点BC间距离.

解析:(1)飞机水平方向上,由abc做匀加速直线运动,由ΔxaT2得,a===10 m/s2.

(2)因位置b对应ac过程的中间时刻,故有vb==50 m/s.

(3)设物体落地时间为t,由hgt2得:t= =4 s,BC间距离为:BCbc+vctvbt

vcvbaT,得:BCbc+aTt=95 m.

答案:(1)10 m/s2 (2)50 m/s (3)95 m

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10.

图4-1-28

(2010·西安质检)质量为0.2 kg的物体,其速度在xy方向的分量vxvy与时间t的关系如图4-1-28所示,已知xy方向相互垂直,则( )

A.0-4 s内物体做曲线运动

B.0-6 s内物体一直做曲线运动

C.0-4 s内物体的位移为12 m

D.4-6 s内物体的位移为2 m

答案:AD

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9.

图4-1-27

乒乓球在我国有广泛的群众基础,并有“国球”的美誉,中国乒乓球的水平也处于世界领先地位.现讨论乒乓球发球问题,已知球台长L、网高h,假设乒乓球反弹前后水平分速度不变,竖直分速度大小不变、方向相反,且不考虑乒乓球的旋转和空气阻力.若球在球台边缘O点正上方某高度处以一定的速度被水平发出(如图4-1-27所示),球恰好在最高点时越过球网,则根据以上信息可以求出( )

A.发球的初速度大小          B.发球时的高度

C.球从发出到第一次落在球台上的时间  D.球从发出到对方运动员接住的时间

解析:由运动对称性可知,发球位置距球台的高度等于网高h,发球点到球第一次落在台上P1点的水平距离为L/4,根据平抛运动的规律hgt2,=v0t,由此两式可求出发球时的速度v0和球从发出到第一次落在台上的时间t,所以A、B、C项均正确;但由于不知道对方运动员在何处接住球,故无法求出总时间,D项错误.

答案:ABC

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