问题 多选题

如图所示,甲、乙两物体在同一条直线上运动,折线是物体甲运动的图象,直线是物体乙运动的图象,则下列说法正确的是(  )

A.甲、乙两物体运动方向相反

B.甲做匀速直线运动,速度大小为7.5m/s

C.乙做匀减速直线运动,加速度是-5m/s2

D.甲、乙两物体在距甲的出发点60m处相遇

答案

A.位移-时间图象的斜率等于物体运动的速度,由图可知:甲的斜率为正,故速度方向为正,乙的斜率为负,故速度方向为负,故A正确;

B.甲前2s先做匀速直线运动,甲的斜率为:

40
2
=20,所以此时间内速度大小为20m/s,故B错误;

C.由图象可知,乙做匀速运动,故C错误;

D.由图象可知:甲乙在8s末相遇,相遇时的位置距原点60m,故D正确.

故选AD.

单项选择题
阅读理解

阅读理解

     However important school life may be, we can't ignore the fact that children spend more time at home

than in the classroom.Therefore the great influence of parents can't be ignored or discounted by the

teacher.They can become strong supports of the school or they can consciously or unconsciously prevent

the school from accomplishing its aims.

     Administrators have been aware of the need to keep_parents_apprised_of the newer methods used in

schools.Many principals have conducted workshops explaining such matters as the reading readiness

program and developmental math.

     Moreover, the classroom teacher can also play an important role in explaining to parents what they

should do.The informal tea and many interviews carried on during the year, as well as new ways of

reporting pupils' progress, can significantly aid the interchange of ideas between school and home.

     Suppose that a father has been drilling Junior in arithmetic processes night after night. In a friendly

interview, the teacher can help the parent change his method.He might be persuaded to let Junior

participate in discussing the family budget, buying the food, using a measuring cup at home, setting the

clock, calculating mileage on a trip and engage in scores of other activities that have a mathematical basis.

     If the father follows the advice, it is reasonable to assume that he will soon realize his son is making

satisfactory progress in math and at the same time, enjoying the work.

     Too often, however, teachers' conferences with parents are devoted to unimportant accounts of

children' s wrongdoing, complaints about laziness and poor work habits, and suggestions for punishments

and rewards at home.

     What is needed is a more creative approach in which the teacher, as a professional advisor, plants

ideas in parents'minds for the best use of the many hours that the child spends out of the classroom.In

this way, the school and the home join forces in fostering the fullest development of youngsters'competence.

1. The underlined phrase"keep parents apprised of"in Para.2 probably means to let parents________.

A. judge  

B. know

C. design  

D. develop

2. What is the purpose of the schools' informal tea and interviews?

A. To improve the relationship between teachers and parents.

B. To explain to parents the change of the school curriculum.

C. To report students' misdoings and suggestions for punishments.

D. To help develop good communication between school and home.

3. Why does the author provide the example in Paragraph 4?

A. To help parents know the importance of home activities.

B. To show how the teacher can guide in home training.

C. To prove parents are nonprofessional advisors.

D. To advice parents to teach kids math at home.

4. From the passage we learn that the author________.

A. thinks teachers should do better as professionals

B. is worried about children' s performance at home

C. is satisfied with the present state of school education

D. believes time spent out of the classroom has been wasted