问题 选择题

如图所示,质量为m、顶角为α的直角劈和质量为M的正方体放在两竖直墙和水平面间,处于静止状态.若不计一切摩擦,则

A.水平面对正方体的弹力大小为

B.墙面对正方体的弹力大小

C.正方体对直角劈的弹力大小为

D.直角劈对墙面的弹力大小

答案

AB

题目分析:对正方体和直角劈的整体而言,竖直方向;水平方向墙面对正方体的弹力大小等于墙面对直角劈的弹力;对直角劈的受力图如图所示,则墙面对直角劈的弹力为;所以墙面对正方体的弹力大小;正方体对直角劈的弹力大小。选项AB正确。

完形填空

A young man was getting ready to graduate from college. He had wanted a beautiful  1  in a dealer’s showroom, and knowing his father could well   2  it, he told him that was all he wanted.
As Graduation Day came near, the young man expected   3   that his father had bought the gift.   4 , on the morning of his graduation, his father called him into his own   5 . His father told him how proud he was to have such a fine son, and told him how much he loved him. He   6  his son a beautifully wrapped gift box. Curious, and somewhat   7 , the young man opened the box and found a lovely leather bound Bible,with the young man’s name written in gold. Angry, he  8  his voice to his father, and said, “With all your money you give me a Bible?” and  9   out of the house.
Many years passed and the young man was very   10  in business. He had a beautiful home and wonderful family, but   11  his father was very old, and thought perhaps he should go to see him.   12  he could make arrangements, he received a telegram   13  him his father had passed away and willed all of his 14  to his son. When he arrived at his father’s, sudden sadness and regret   15 his heart. He began to   16  his father’s important papers and saw the still new gift-wrapped Bible, just as he had   17  it years ago. With tears, he opened the Bible and began to turn the pages. His father had carefully   18  a verse(诗), Matthew 7-11,“And if you, being evil, know how to give good gifts to your children, how much more shall your Heavenly Father which is in Heaven, give to those who ask Him?”
As he read those words, a car key  19  from the back of the Bible. It had a tag(标签) with the dealer’s name, the same dealer who had the sports car he had desired. On the tag was the   20  of his graduation, and the words: PAID IN FULL.
小题1:
A.computerB.bikeC.carD.recorder
小题2:
A.payB.buyC.supportD.afford
小题3:
A.signsB.factsC.marksD.results
小题4:
A.HoweverB.FinallyC.QuietlyD.Actually
小题5:
A.houseB.roomC.studyD.office
小题6:
A.gaveB.handedC.showedD.presented
小题7:
A.excitedB.nervousC.interestedD.disappointed
小题8:
A.raisedB.changedC.improvedD.increased
小题9:
A.ranB.wentC.walkedD.stormed
小题10:
A.busyB.successfulC.comfortableD.happy
小题11:
A.rememberedB.realizedC.knewD.considered
小题12:
A.WhenB.AsC.AfterD.Before
小题13:
A.informingB.announcingC.tellingD.discovering
小题14:
A.treasuresB.possessionsC.clothingD.eagerness
小题15:
A.filledB.caughtC.attackedD.beat
小题16:
A.pick upB.remind ofC.search throughD.refer to
小题17:
A.seenB.gotC.leftD.thrown
小题18:
A.madeB.writtenC.underlinedD.designed
小题19:
A.droppedB.appearedC.rolledD.showed
小题20:
A.yearB.dateC.momentD.Day
选择题