质量为2kg的物体,在光滑水平面上受到两个水平共点力的作用,以8m/s2的加速度

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问题:

质量为2kg的物体,在光滑水平面上受到两个水平共点力的作用,以8m/s2的加速度作匀加速直线运动,其中F1与加速度方向的夹角为30°,某时刻撤去F1,此后该物体(  )

A.加速度可能为5m/s2

B.加速度可能为4m/s2

C.加速度可能为3m/s2

D.加速度可能为2m/s2

考点:滑动摩擦力、动摩擦因数力的合成牛顿第二定律
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黄金:盎司:克

A.质量:千克:公斤

B.股票:美元:人民币

C.汽油:加仑:升

D.铜:吨:磅

题型:多选题

阅读理解。

     Once there was a young woman who didn't like her job. Every day when she came home from work, she

told her husband how terrible her day had been, how tiring the work and how unreasonable her boss. "Leave

that job," her husband told her.

     "Oh, I will," she said."But not yet. I have too many friends there for me to leave." And so she remained

unhappy at work until the years became decades and her children had children."Leave that job", her grandchildren told her."Oh, I will," she said."But not yet. There are only seven more years until I reach thirty years of service and can retire. So I can't just yet."

     I know this woman. And her story reminds me of an old dog half asleep on the porch of a general store,

moaning and groaning in the sun."Why is your dog acting that way?" a customer asked the store owner." Oh",

answered the man,"He's lying on a nail." "Well, why doesn't he move?""Because it's not hurting him bad

enough."

     That's true for people, too. We convince ourselves the pain is not bad enough to leave the workplace we

know. But we are wrong. Prolonged work pain is continuing. Some work pain damages our self-esteem, kills

our passion or destroys our dreams.

     Wilbur Wright once commented,"We could hardly wait to get up in the morning. I know that exhilarating

feeling of being so passionate about something I was working on that I couldn't wait to get back to work. And

people who are winning at working know that kind of passion, too." They get excited about work.

     They offer their unique gifts and talents eagerly. And when things don't change as they sometimes will, they

refuse to let environment hijack their self-esteem, passion or dreams.

1. The woman complained to her husband every day because_______.

A. she didn't have enough money to support her family

B. her boss criticized her for what she had done

C. she was not satisfied with her job at all

D. her work was difficult and her boss was cruel

2. The author mentioned the old dog in order to tell us that _______.

A. it was deeply hurt by its owner

B. the woman is like the dog on the nail

C. it is tied firmly to a nail by its owner

D. it should be injured badly enough

3. The underlined word" Prolonged"( in Paragraph 4) means________.

A. lasting

B. slight

C. serious

D. hard

4. People who are getting along well with their work ________.

A. have to get up early every day

B. are not willing to go to work

C. need more unique gifts and talents

D. are likely to change with the situation

题型:多选题

刚从烘箱里取出来的烘好的面包,老远就能闻到面包的香味;这是因为______.当面包冷下来之后,香味就渐渐减少了,这是因为______.

题型:多选题

女,43岁。无症状,常规体检。查体:右侧下腹扪及包块,无压痛。辅助检查:泌尿系统B超提示双肾大小、形态正常;肾脏B超立位比卧位下降4cm。

较恰当的治疗为()

A.门诊随访

B.手术治疗

C.口服药物治疗

D.物理治疗

E.静脉抗感染治疗

题型:多选题

A级柜员的授权业务范围()涵盖B级柜员的授权业务范围,只要B级柜员在岗,需B级柜员授权的业务()由Q级柜员代替授权。

A.可以,允许

B.可以,不允许

C.不可以,允许

D.不可以,不允许

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