质量为7t(吨)的原来静止的汽车,在3500N牵引力的牵引下沿水平直线运动40s

题型:问答题

问题:

质量为7t(吨)的原来静止的汽车,在3500N牵引力的牵引下沿水平直线运动40s,然后在2800N牵引力的牵引下沿水平直线运动3min,最后将牵引力撤消,汽车滑行20m后停止,全过程共用时间230s.设全过程汽车所受的摩擦阻力相同,求:

(1)牵引力撤消后,汽车滑行的加速度大小;

(2)汽车所受摩擦力的大小;

(3)全过程汽车行驶的路程.

考点:滑动摩擦力、动摩擦因数力的合成共点力的平衡牛顿第二定律动能定理
题型:问答题

阅读理解。

     Some people bring out the best in you in a way that you might never have fully realized on your own.

My mom was one of those people.

     My father died when I was nine months old, making my mom a single mother at the age of eighteen.

While I was growing up, we lived a very hard life. We had little money, but my mom gave me a lot of love.

Each night, she sat me on her lap and spoke the words that would change my life, "Kemmons, you are

certain to be a great man and you can do anything in life if you work hard enough to get it."

     At fourteen, I was hit by a car and the doctors said I would never walk again. Every day, my mother

spoke to me in her gentle, loving voice, telling me that no matter what those doctors said, I could walk again

if I wanted to badly enough. She drove that message so deep into my heart that I finally believed her. A year

later, I returned to school - walking on my own!

     When the Great Depression (大萧条) hit, my mom lost her job. Then I left school to support the both

of us. At that moment, I was determined never to be poor again.

     Over the years, I experienced various levels of business success. But the real turning point occurred on

a vacation I took with my wife and five kids in 1951. I was dissatisfied with the second-class hotels available

for families and was angry that they charged an extra $2 for each child. That was too expensive for the

average American family. I told my wife that I was going to open a motel (汽车旅馆) for families that would

never charge extra for children. There were plenty of doubters at that time.

     Not surprisingly, mom was one of my strongest supporters. She worked behind the desk and even

designed the room style. As in any business, we experienced a lot of challenges. But with my mother's

words deeply rooted in my soul, I never doubted we would succeed. Fifteen years later, we had the largest

hotel system in the world-Holiday Inn. In 1979 my company had 1,759 inns in more than fifty countries

with an income of $ 1 billion a year.

     You may not have started out life in the best situation. But if you can find a task in life worth working for

and believe in yourself, nothing can stop you.

1. What Kemmons' mom often told him during his childhood was ______.

A. caring

B. moving

C. encouraging

D. interesting

2. According to the author, who played the most important role in making him walk back to school again?

A. Doctors.

B. Nurses.

C. Friends.

D. Mom.

3. What caused Kemmons to start a motel by himself?

A. His terrible experience in the hotel.

B. His previous business success of various levels.

C. His moms support.

D. His wife's suggestion.

4. Which of the following best describes Kemmons' mother?

A. Modest, helpful, and hard-working.

B. Loving, supportive and strong-willed.

C. Careful, helpful and beautiful.

D. Strict, sensitive and supportive.

5. Which of the following led to Kemmons' success according to the passage?

A. Self-confidence, hard work, higher education and a poor family.

B. Mom's encouragement, clear goals, self-confidence and hard work.

C. Clear goals, mom's encouragement, a poor family and higher education.

D. Mom's encouragement, a poor family, higher education and opportunities.

题型:问答题

高钾血症紧急治疗,不包括()

A.10%葡萄糖酸钙缓慢静注

B.葡萄糖加胰岛素静滴

C.5%碳酸氢钠缓慢静注

D.透析

E.口服螺内酯利尿

题型:问答题

我想网上查询个人社保,但需要登录密码,不知初始密码是多少?试过身份证后六位和123456都不行。还有如果以后忘记了查询密码怎么办?

题型:问答题

阅读下列说明和数据流图,回答问题1至问题3,将解答填入对应栏内。

[说明]

某图书馆管理系统的主要功能是图书管理和信息查询。对于初次借书的读者,系统自动生成读者号,并与读者基本信息(姓名、单位、地址等)一起写入读者文件。

系统的图书管理功能分为4个方面:购入新书、读者借书、读者还书和图书注销。

(1)购入新书时需要为该书编制入库单。入库单内容包括图书分类目录号、书名、作者、价格、数量和购书日期,将这些信息写入图书目录文件并修改文件中的库存总量(表示到目前为止,购入此种图书的数量)。

(2)读者借书时需填写借书单。借书单内容包括读者号和所借图书分类目录号。系统首先检查该读者号是否有效,若无效,则拒绝借书;若有效,则进一步检查该读者已借图书是否超过最大限制数(假设每位读者能同时借阅的书不超过5本),若已达到最大限制数,则拒绝借书;否则允许借书,同时将图书分类目录号、读者号和借阅日期等信息写入借书文件中。

(3)读者还书时需填写还书单。系统根据读者号和图书分类目录号,从借书文件中读出与该图书相关的借阅记录,标明还书日期,再写回到借书文件中,若图书逾期,则处以相应的罚款。

(4)注销图书时,需填写注销单并修改图书目录文件中的库存总量。

系统的信息查询功能主要包括读者信息查询和图书信息查询。其中读者信息查询可得到读者的基本信息以及读者借阅图书的情况:图书信息查询可得到图书基本信息和图书的借出情况。

图书管理系统的顶层数据流图如图15-1所示,图书管理系统的第0层数据流图如图15-2所示,其中加工2的细化图如图15-3所示。

数据流图15-2中有两条数据流是错误的,请指出这两条数据流的起点和终点。

题型:问答题

对养护资料的检查核对内容包括()。

A.养护项目安排是否合理

B.资料是否齐全

C.记录内容是否齐全

D.资料先后关系是否合理

E.资料内容是否符合格式要求

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