问题 选择题

图所示的情景中,关于力对物体做功的叙述,正确的是

答案

答案:C

题目分析:A、举重运动员举着杠铃不动,运动员给杠铃一个向上的力,杠铃向上没有移动距离,运动员对杠铃没有做功.不符合题意.

B、人推汽车但没有推动,人给汽车一个向左的力,汽车向左没有移动距离,人对汽车没有做功.不符合题意.

C、起重机吊着重物上升,钢绳给重物一个向上的力,重物向上移动了距离,钢绳对重物做功.符合题意.

D、足球的重力竖直向下,足球在水平地面上滚动,没有向下运动,重力对足球没有做功.不符合题意.

故选C.

点评:有力有距离,力对物体不一定做功,物体必须在力的作用下通过了距离,力对物体才做功.

单项选择题
完形填空

第一节 完形填空(共10小题;每小题2分,满分20分)

阅读下面短文,掌握其大意,然后从21—30各题所给的A、B、C和D项中,选出最佳选项,并在答题卡上将该项涂黑。

How a person reacts to criticism often means the difference between success and failure.Take Ole Bull for example. His  21   father,a chemist,wanted him to study for the ministry and forbade him to play his beloved(心爱的)violin. He soon gave up the course and,disobeying his father, 22  all his time and energy to the violin.

Unfortunately,though he had great ability,his teachers were   23  unskilled,so that by the time he was ready to start his concert tour he wasn't prepared. In Italy a Milan newspaper critic(批评家)wrote:“He is a(n)   24   musician.If he is a diamond,he is certainly in the rough and unpolished.”There were two ways Ole Bull could have    25   to that criticism.He could have let it make him angry,or he could learn from it.Fortunately he chose the   26 .He went to the newspaper office and asked to see the critic.The   27   editor introduced him. Ole spent the evening with the 70 year old critic,asked about his faults,and sought the old man's

28   on how to correct them.Then he cancelled the rest of his tour,returned home,and   29   the next six months studying under really able teachers. He practiced hour after hour to overcome his   30 .Finally,he returned to his concerts and,when only 26, became the wonder of Europe.

21.A.awkward     B generous       C.stubborn      D.confident

22.A.devoted       B donated        C.supplied      D. allocated

23.A.absolutely    B.completely  C relatively       D.gradually

24.A.untrained     B.gifted        C.mature        D.1eading

25.A.referred       B.attracted     C.affected      D.reacted

26.A.former        B.1atter        C.1ater          D.early

27.A.frightened    B ashamed       C.astonished    D convinced

28  A.advice         B.attitude      C.virtue         D wisdom

29.A.totaled       B.squeezed      C.spent          D.spared

30.A.mistakes     B.troubles       C.difficulties   D.faults