【单选题】
光滑接触面对物体的约束反力，作用在接触面处，其合力的方向___
A. 沿法线方向指向该物体，为压力
B. 沿法线方向指向该物体，为拉力
C. 沿法线方向背离该物体，为压力
D. 沿法线方向背离该物体，为拉力
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相关试题
【单选题】
下列关于力偶的说法错误的是___。
A. 力偶不能用一个力来等效
B. 力偶能用一个力来平衡
C. 力偶对其作用平面内任一点的力矩，恒等于其力偶矩
D. 力偶在任意坐标轴上的投影均等于零
【单选题】
已知梁某个截面上受到集中力偶作用，则其对应的弯矩图___
A. 突变
B. 转折
C. 不变
D. 无法确定
【单选题】
下列关于轴向拉压杆内力说法正确的是___
A. 轴力以拉为正
B. 轴力以压为正
C. 轴力大小与截面尺寸有关
D. 轴力大小与杆件长度有关
【单选题】
当杆件发生剪切变形时，其相邻横截面___
A. 产生相对转动
B. 产生相对错动
C. 同 时 变 大
D. 同 时 变 小
【单选题】
两端铰支的等截面细长压杆，其欧拉公式中的长度系数为___
【单选题】
以下属于扭矩正负号判断方法的是___
A. 右手螺旋法则
B. 左上右下矩为正
C. 逆 正 顺 负
D. 左 顺 右 逆 矩 为 正
【单选题】
画弯矩图时，均布荷载作用梁段，其弯矩图形状为___
A. 水平直线
B. 斜直线
C. 突变
D. 抛物线
【单选题】
一个构件处于平衡状态，利用平衡方程，最多可以求解___个未知力。
【单选题】
以下属于力偶正负号判断方法的是___
A. 右 手 螺 旋 法 则
B. 逆 正 顺 负
C. 拉 正 压 负
D. 左 顺 右 逆 为 正
【单选题】
下列关于梁剪力的说法，正确的是___
A. 剪力以向上为正
B. 剪力以向下为正
C. 支座截面剪力为零
D. 剪力为零处，弯矩有极值
【单选题】
平面汇交力系的独立平衡方程数目为___。
【单选题】
一力 F 的大小为 60KN，其在 X 轴上的分力的大小为 30KN，力 F 与 X 轴的夹角 应 为 ___。
A. 60°
B. 无法确定
C. 30°
D. 90°
【单选题】
___。
A. 与 x 轴 垂 直
B. 与 x 轴 平 行
C. 与 y 轴 垂 直
D. 通 过 坐 标 原 点 O
【单选题】
在同一坐标轴上投影相等的两个力___
A. 一 定 相 等
B. 一 定 不 相 等
C. 大小相等，但方向相反
D. 可能相等可能不相等
【单选题】
虎克定律应用的条件是___。
A. 只适用于塑性材料
B. 只适用于轴向拉伸
C. 应力不超过比例极限
D. 应力不超过屈服极限
【单选题】
横截面面积相等、材料不同的两等截面直杆，承受相同的轴向拉力，则两杆的 ___ 。
A. 轴力相同，横截面上的正应力不同
B. 轴力相同，横截面上的正应力也相同
C. 轴力不同，横截面上的正应力相同
D. 轴力不同，横截面上的正应力也不同
【单选题】
___。
A. 正 比
B. 反 比
C. 不 成 比 例
D. 不 成 反 比
【单选题】
构件抵抗变形的能力称___。
A. 刚度
B. 强度
C. 稳定性
D. 极限强度
【单选题】
构件抵抗破坏的能力___。
A. 刚度
B. 强度
C. 稳定性
D. 极限强度
【单选题】
构件保持原来平衡状态的能力称___。
A. 刚度
B. 强度
C. 稳定性
D. 极限强度
【单选题】
杆件的变形与杆件的___有关。
A. 外力
B. 外力、截面大小
C. 外力、截面大小、材料
D. 外力、截面大小、杆长、材料
【单选题】
下列与弯曲梁截面上正应力大小无关的因素是 ___
A. 截面尺寸
B. 截面形状
C. 荷载
D. 材料强度
【单选题】
合力等于零的力系称为___。
A. 等效力系
B. 平衡力系
C. 一般力系
D. 互等力系
【单选题】
下列说法正确的是___。
A. 力的三要素为大小、方向、矩心
B. 二力平衡公理适用于变形体
C. 力的作用效应为变形效应
D. 合力不一定大于分力
【单选题】
关于力偶说法正确的是___。
A. 力偶无合力
B. 力偶大小与矩心位置有关
C. 力偶在作用平面内不能任意移动
D. 力偶可以和一个力等效
【单选题】
以下作用力属于约束反力的是___。
A. 重力
B. 支持力
C. 水压力
D. 土压力
【单选题】
以下关于梁的剪力和弯矩说法正确的是___
A. 剪力为零的截面，弯矩也必定为零
B. 剪力最大的截面，弯矩也必定最大
C. 剪力为零的截面，弯矩有极值
D. 剪力最大的截面，弯矩为零
【单选题】
以下关于弯曲正应力说法正确的是___。
A. 截面弯矩越大，弯曲正应力越大
B. 点距离中性轴越远，弯曲正应力越小
C. 截面高度越高，弯曲正应力越大
D. 截面宽度越大，弯曲正应力越大
【单选题】
以下关于弯曲切应力说法正确的是___。
A. 截面剪力越大，弯曲切应力越小
B. 点距离中性轴越远，弯曲切应力越小
C. 工字型截面翼缘切应力最大
D. 工字型截面腹板切应力均匀分布
【单选题】
以下关于惯性矩说法正确的是___
A. 惯性矩可能为负值
B. 矩形截面惯性矩与截面宽度无关
C. 空心圆形截面惯性矩比相同面积实心圆形截面小
D. 惯性矩越大，抗弯能力越好
【单选题】
力在坐标轴上的投影是___。
A. 矢量
B. 几何量
C. 代数量
D. 以上都不是
【单选题】
二力杆的受力特征是杆件两端约束反力的方向一定是沿着___方向。
A. 力的作用线
B. 两个作用点的连线
C. 杆件轴线
D. 以上都不是
【单选题】
等截面直杆承受轴向拉力 P 作用，若选用三种不同的截面形状：圆形、正方形、空心圆，试比较材料用量，正确的是___。
A. 正方形截面最费料
B. 圆形截面最省料
C. 空心圆最省料
D. 三者用料相同
【单选题】
某木杆的截面积为 A= 100mm²，在 P＝2KN 的外力作用下，木杆横截面上的正应 力 为 ___。
A. 0.2MPa
B. 2MPa
C. 20MPa
D. 200MPa
【单选题】
某钢杆的截面积为 A=6cm²，在 P=30KN 的外力作用下，钢杆横截面上的正应力为 ___。
A. 0.5MPa
B. 5MPa
C. 50MPa
D. 500MPa
【单选题】
某钢筋混凝土压杆的截面积为 A=400cm²，在 P=600KN 的外力作用下，压杆横截面上的正应力为___。
A. 0.15MPa
B. 1.5MPa
C. 15MPa
D. 150MPa
【单选题】
受压直杆突然发生弯曲而导致折断破坏的现象称为___。
【单选题】
临界力是指压杆在___所受到的最大压力。
A. 稳定状态
B. 临界状态
C. 不稳定状态
D. 破坏状态
推荐试题
【单选题】
According to Dr. White, what should the government do to build more green spaces in cities? ___
A. Find financial support.
B. Improve urban planning.
C. Involve local residents in the effort.
D. Raise public awareness of the issue.
【单选题】
The survey by the Kaiser Family Foundation is mentioned to illustrate the idea that . ___
A. kids don’t always follow parents’ rules
B. only few parents believe the good news
C. much media use results in bad health
D. parents’ rules make a huge difference
【单选题】
What did the kids do when parents set any time or content limits, according to the Kaiser Family Foundation? ___
A. They cut down on their screen time.
B. They appreciated their parents’ love.
C. They spent more time staying outdoor.
D. They accepted parents’ rules unwillingly.
【单选题】
What will Kenneth Ginsburg most probably suggest that parents should do? ___
A. Avoid setting firm rules.
B. Avoid ruling with an iron grip.
C. Set rules after family discussion.
D. Set rules that are easy to understand.
【单选题】
Margaret Broe -Fitzpatrick finds it impossible. ___
A. to achieve just- right parenting
B. to keep track of everything done by the kids
C. for the kids to face rules alone
D. for the kids to observe rules without protest
【单选题】
The passage is mainly intended for parents . ___
A. whose kids have difficulty in self- discipline
B. whose kids are addicted to media use
C. who have doubts about setting rules
D. who are too busy to care for their kids
【单选题】
The word “it” (Para. 2) most probably refers to. ___
A. the lack of stable communities
B. the breakdown of informal information channels
C. the increased mobility of families
D. the growing number of people moving from place to place
【单选题】
The main problem people may encounter today arises from the fact that . ___
A. they have to learn new things consciously
B. they lack the confidence of securing reliable and trustworthy information
C. they have difficulty obtaining the needed information readily
D. they can hardly carry out casual communications with an extended family
【单选题】
From the passage we can infer that _______. ___
A. electronic mail will soon play a dominant role in transmitting messages
B. it will become more difficult for people to keep secrets in an information era
C. people will spend less time holding meetings or conferences
D. events will be reported on the spot mainly through satellites
【单选题】
Technology facilitates _______. ___
A. sharing information
B. storing and sending information
C. providing people with easy access to more information
D. all of the above
【单选题】
We can learn from the last paragraph that _______. ___
A. it is necessary to obtain as much
B. people should make the best use of the information
C. we should realize the importance of accumulating information
D. it is of vital importance to acquire needed information efficiently
【单选题】
The author thinks that people are _________. ___
A. satisfied with their appearance
B. concerned about appearance in old age
C. far from neglecting what is in fashion
D. reluctant to follow the trends in fashion
【单选题】
Fashion magazines and TV advertisements seem to link fashion to _________. ___
A. confidence in life
B. personal dress
C. individual hair style
D. personal future
【单选题】
Causes of fashions are _________. ___
A. uniform
B. varied
C. unknown
D. inexplicable
【单选题】
Present-day society is much freer and easier because it emphasizes _________. ___
A. uniformity
B. formality
C. informality
D. individuality
【单选题】
Which is the main idea of the last paragraph? ______________ ___
A. Care about appearance in formal situations.
B. Fashion in formal and informal situations.
C. Ignoring appearance in informal situations.
D. Ignoring appearance in all situations.
【单选题】
Permissive parents would ________. ___
A. let their children read any books they like to
B. not let their children see any films they like to
C. not let their children read any books without first checking their contents
D. let their children see the films with their first checking
【单选题】
The fact that parents check the contents of the book or the film for their children to read or see shows __________. ___
A. the necessity of censorship
B. that many books and films are bad
C. that children need their parents to help them understand more
D. that the parents are permissive
【单选题】
Which of the following statements is NOT true?____________ ___
A. Some adults can’t tell right from wrong.
B. Censorship is compared to the law because both of them perform good service to society as a whole.
C. Censors pay attention only to genuine works of art.
D. Censorship is necessary because many books, plays and films are far from being “works of art”.
【单选题】
What does the word “corrupt” in Para.4 mean?__________ ___
A. Make morally bad.
B. Hurt.
C. Injure.
D. Damage.
【单选题】
What would be the best title of this passage?_____________ ___
A. Permissive Parents and Responsible Parents.
B. Censorship and the Law.
C. Censors Value Artistic Merits .
D. Censorship Performs Good Service to Society.
【单选题】
Lie detectors are widely used in the United States because _____________. ___
A. they can help detect people’s emotional stress
B. they can help detect people's physiological changes
C. they can help find out whether a person is telling the truth or not
D. they can measure the subject’s electrical resistance
【单选题】
According to the passage, we know that Britain______________. ___
A. will adopt lie detectors widely
B. will adopt lie detectors on a smaller scale
C. adopt lie detectors
D. has not decided whether to adopt lie detectors or not
【单选题】
The tests themselves are by no means free from error..." (Line 1-2.Para.3) means ____________. ___
A. the tests definitely have no error
B. the tests sometimes make mistakes
C. the polygraphers do not make mistakes
D. the polygraphers can avoid error by using some techniques
【单选题】
Which of the following is true? ________________ ___
A. The tests are conducted by qualified polygraphers.
B. Innocent people may blush or stammer when questioned.
C. Guilty people can definitely be found out by answer questions
D. Guilty people may escape by refusing to answer questions.
【单选题】
What troubles lie detector researchers most is that _______________. ___
A. innocent people are convicted crimes
B. innocent people will learn to tell lies
C. lie detectors may cause industrial unrests
D. lie detectors are sometimes not dependable
【单选题】
In the passage the author's attitude towards "mixed-ability teaching" is _______. ___
A. critical
B. questioning
C. approving
D. objective
【单选题】
By "held back" (Line 1) the author means _____. ___
A. made to remain in the same classes
B. forced to study in the lower classes
C. drawn to their studies
D. prevented from advancing
【单选题】
The author argues that a teacher's chief concern should be the development of the student's _________. ___
A. personal qualities and social skills
B. total personality
C. learning ability and communicative skills
D. intellectual ability
【单选题】
Which of the following is NOT MENTIONED in the third paragraph? __________ ___
A. Group work gives pupils the opportunity to learn to work together with others.
B. Pupils also learn to develop their reasoning abilities.
C. Group work provides pupils with the opportunity to learn to be capable organizers.
D. Pupils also learn how to participate in teaching activities.
【单选题】
The author's purpose in writing this passage is to ______. ___
A. argue for teaching bright and not-so-bright pupils in the same class
B. recommend pair work and group work for classroom activities
C. offer advice on the proper use of the library
D. emphasize the importance of appropriate formal classroom teaching
【单选题】
According to the author, the deaths among youth are mainly caused by _____. ___
A. traffic accidents
B. smoking-related diseases
C. murder
D. all of these
【单选题】
Every day there are over_____high school students who will become regular smoker. ___
A. 75
B. 23
C. 30
D. 3000
【单选题】
By "dropout" the author means______. ___
A. students who failed the examination
B. students who left school
C. students who lost their way
D. students who were driven out of school
【单选题】
The reason for declining adolescent smoking is that ________. ___
A. NCI has taken effective measures
B. smoking is prevented among high school seniors
C. there are many smokers who have died of cancer
D. not stated
【单选题】
What is implied but not stated by the author is that ________. ___
A. smoking rates among youth have declined very little
B. there are now more female than male smokers among high school seniors
C. high smoking rates are due to the increase in wealth
D. smokers at high school are from low socio-economic backgrounds
【单选题】
According to the passage, which of the following is NOT a disadvantage of part time education? _______________ ___
A. It requires some break in one's career.
B. It tends to last too long for many people to complete a degree program.
C. It affects one's career.
D. It gives the student less time to share with the family.
【单选题】
Which of the following is NOT an advantage of distance learning? _________ ___
A. The student may choose his or her own pace.
B. The student may study at any time to his or her convenience.
C. They can pursue their chosen career while studying.
D. Their tutorial assistance comes through regular airmail, telephone, etc.
【单选题】
What benefit will distance learning program bring to a business? __________ ___
A. Recruitment of more talented people.
B. Good image of the business.
C. Better cooperation with universities.
D. Further training of employees and business growth.
【单选题】
Good distance learning program have the following characteristic EXCEPT______. ___
A. distance learning course is the same as students taking courses in campus
B. the degree should be same as on campus study
C. professor-student relationship is strictly one to one all through the course
D. includes subject evaluation tool
