问题 单项选择题

一个质点做变速直线运动的v-t图像如下图,下列说法中正确的是:()

A.第1s内与第5s内的速度方向相反

B.第1s内的加速度大于第5s内的加速度

C.OA、AB、BC段的加速度大小aBC>aOA>aAB

D.OA段的加速度方向与速度方向相反

答案

参考答案:C

解析:

v-t图象中,与时间轴平行的直线表示做匀速直线运动,倾斜的直线表示匀变速直线运动,斜率表示加速度,图象与坐标轴围成的面积表示位移.在时间轴上方的位移为正,下方的面积表示位移为负.看物体是否改变运动方向就看速度图象是否从时间轴的上方到时间轴的下方.

A.第1s内与第5s内的速度图象都在时间轴的上方,都为正,方向相同,故A错误;

第3s内质点处于匀速直线运动状态,故②错误;

B.C.斜率表示加速度,倾斜度越大,加速度越大,从图可以看出aBC>aOA>aAB,故B错误,C正确;

D.OA段的加速度与速度方向都为正,相同,故D错误.

故选C.

完形填空

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第二节:完形填空(兆20小题;每小题1分,满分20分)

阅读下面短文,掌握其大意,然后从21-40各题所给的四个选项(A、B、C和D)中,选出最佳选项,并在答卷纸上将该选项标号涂黑。

Temperature is part of my married romance Coming to New’York from Baltimore-where there is just one small snowstorm each year-1was  21  by a fireplace in my new home,wit fires  22  all day,just as what ancient people did at a wedding.

My husband,Peter,comes from northem Ontario,where winter  23  from September to May and cold wind is  24 .”When Canadians have 30 below,they  25  it,”he says.“Cold wind is for crybabies.”

So to marry this man I had to learn to  26  for serious cold. To get me from Baltimore's Inner Harbor to Albany’s frozen Hudson,Peter piled me  27  jackets and sweaters,scarves and gloves.even a hat with earflaps.The gift of Sorel boots-comfortably warm at Canada’s 30 below,was a  28  we were getting serious.

That first winter together,living in upstate New York,I thought I’d  29  My boots were good below freezing,but my fingers could  30  tie them.Physical adaptation is real,but it came slowly.And there is also emotional  31  to cold.Some days I tell myself that I have enough beach memories to stick to on  32  days and other days I am reminded that living cold does indeed build  33 .

34 ,having a warm house is important.After my first marriage ended,for years I 35   ! went on a second date with a man whose response to my”I'm cold”was.”Put on a sweater.”Now I’m married to a man who  36  that cold hands do not mean a warm heart.And that a big oil bill is better than roses But surprisingly,I've grown,too.I am  37 ,in this new life and climate,to go look for that cost-saving sweater.

The word comfortable did not  38  refer to being contented.Its Latin root,comfortare, means to strengthen.The Holy Spirit is Comforter;not to make us comfortable,but to make us

39 .we  40  not be warm but we are indeed comforted.

21.A.set down          B.set about          C.set up          D.set out

22.A.lighting           B.burning            C.going           D.flashing

23.A.appears           B.starts             C.keeps           D.runs

24.A.something         B.everything        C.nothing         D.none

25.A.suggest           B.mean              C.overlook        D.enjoy

26.A.wear             B.stand              C.dress          D.ride

27.A  under            B.over               C.inside          D.with

28.A.remark           B.sign               C.warning        D.show

29.A.sleep             B.forget             C.die            D.continue

30.A.hardly            B.easily             C.tightly          D.loosely

31.A.health            B.reaction          C.feelings         D.adaptation

32.A.rainy             B.freezing           C.sunny          D.happy

33.A.character         B.love              C.hope           D.hardship

34.A.Meanwhile        B.However          C.Therefore       D.Besides

35.A.merely            B.ever             C.never           D.just

36.A.wonders          B.knows            C.states           D decides

37.A.unable            B.accustomed       C.interested       D.willing

38.A.originally          B.exactly           C.actually         D.namely

39.A.wild              B.cold              C.strong          D.warm

40.A.will              B.must              C.can            D.may

多项选择题