一电动机通过一质量不计的绳子从静止开始向上提起质量为2.0kg的物体,在前2.0

题型:问答题

问题:

一电动机通过一质量不计的绳子从静止开始向上提起质量为2.0kg的物体,在前2.0s内绳的拉力恒定,此后电动机一直以额定功率工作,物体被提升到50m高度时恰开始以15m/s的速度匀速上升。如图所示为上述过程的v-t图。(g取10m/s2)试求:(结果保留两位有效数字)

(1)电动机的额定功率。

(2)物体从静止开始被提升至开始匀速所需时间。

考点:功率
题型:问答题

下列句子中划线词语能被括号中的词语替换且不改变句意的一项是(     )

A.为了完善领导干部行为规范,健全党内责任追究制度,中 * * 政治局审议并通过了《关于实行党政领导干部问责的暂行规定》。(审查)

B.智者和愚者的区别,不仅仅在于天赋的差异,更在于面对困境,愚者往往束手无策,而智者却能化解困难,走出一条新路。(一筹莫展)

C.这伙人利用人民群众对党和政府的信赖,伪装成政府机关工作人员,到处招摇撞骗,其手段之卑劣已达到了登峰造极的地步。(叹为观止)

D.杭州西溪湿地有着典型的江南水乡风光:水网密布,小桥玲珑,绿树婆娑,亭宇古朴,处处富有诗情画意。(典范)

题型:问答题

截肢后运动功能障碍的主要原因是()。

A.术后长期置于不良肢体位

B.残肢不合理固定

C.失用性萎缩

D.软组织肿胀

E.瘢痕挛缩

题型:问答题
完形填空.
     From the window of my room,l could see a tall cotton-rose hibiscus(木棉树).In spring,
when green leaves were half__1__by mist(薄雾),the tree looked very charming dotted with
red blossom. This__2__neighbor of mine often set my mind working.I__3__regarded it as
my best friend.
     However, when I opened the window one morning,__4__, the tree was almost bare as
a result of the storm the night before.__5__by the situation, I was seized with sadness at
the thought" all the blossom is doomed to(注定 )fall". I couldnot help__6__with emotion :
thecourse of life never runs__7__, for there are so many ups and downs. The__8__of my
life saw my beloved friends parting one after another. Isn't it__9__to the tree shedding
(脱落) its flowers in the wind?
     This event faded from my__10__as time went by. One day after I came home from
the countryside,l found the room hot and casually opened the window. Something outside
__11__my eye and dazzled me. It was a plum tree all red with blossom__12__beautifully
by the sunset. The suprise discovery overwhelmed me with pleasure.I__13__why I had
no idea of some unyielding(顽强的) lifesprouting (发芽) over the fallen petals (花瓣)
when I was__14__for the hibiscus.
     When the last petal dropped , all the joyful admiration for the hibiscus sank into
oblivion(忘却) asif nothing was__15__,until the landscape was again bright with the red
plum blossom to__16__people of life's changing and continuance. Can't it be said that
life is actually a symphony,a harmonious composition of loss and__17__.
Standing by the window lost in__18__for a long time, I realized that no scenery in the
world__19__unchanged. As long as you keep your heart bathing in the sun, every dawn
will__20__a fine prospect for you to unfold and the world will always be about new
hopes.

( )1.A. hidden
( )2.A. interesting
( )3.A. immediately
( )4.A. to my joy
( )5.A. Struck
( )6.A. complaining
( )7.A. pleasant
( )8.A. changes
( )9.A. same
( )10.A. brain
( )11.A. grasped
( )12.A. set off
( )13.A. asked
( )14.A. nervous
( )15.A. kept
( )16.A. remind
( )17.A. harvest
( )18.A.attention
( )19.A.lasts
( )20.A.present

B. revealed
B. amusing
B. gradually
B. to my relief
B. Hit
B. working
B. polite
B. performance
B. popular
B. memory
B. fixed
B. set up
B. doubted
B. sorry
B. saved
B. remember
B. earning
B.thought
B.continues
B.form

C. exposed
C. exciting
C. gently
C. to my surprise
C. Awakened
C. crying
C. smooth
C. struggles
C. familiar
C. body
C. caught
C. set down
C. stared
C. missing
C. left
C. recall
C. benefit
C.considemtion
C.remains
C.award

D. shown
D. inspiring
D. softly
D. to my satisfaction
D. Beaten
D. sighing
D. calm
D. revolution
D. similar
D. store
D. pulled
D. set out
D. wondered
D. happy
D. preserved
D. recognize
D. gain
D.expectation
D.holds
D.design

题型:问答题

试题四(共25分)阅读以下关于数据库备份与恢复方面的叙述,回答问题1至问题4。银行金融系统对数据库中的数据安全要求很高,必须在技术层面上采用必要的措施,以保证数据的有效和不丢失。数据库的备份与恢复是保证数据安全的一种基本方法,一般将数据库备份划分为冷备份、热备份和数据导出,而数据导出根据导出数据的范围,又可以分为完全导出、增量导出和累计导出。该金融系统上线初期,整个业务系统采用了内网方式运行,不与外网发生联系。为了保证数据库内部数据的安全,该银行信息中心的刘工提出的备份方案如表4-1所示。

信息中心的李工对刘工的方案提出了异议,认为数据库一旦发生故障,刘工的方案无法做到数据库的实时恢复,会导致业务数据的丢失,银行应该采用数据库冷备份和热备份相结合的方式来完成数据库的备份。

【问题1】(3分)针对金融数据库安全,从技术层面上分析应重点考虑哪些因素?

题型:问答题

当连续5天日平均气温低于(),一般来讲即进入冬期施工阶段。

A.5℃

B.-5℃

C.-8℃

D.0℃

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