问题 选择题

一个质点由静止开始沿直线运动,速度随位移变化的图线如图所示,关于质点的运动下列说法正确的是(  )

A.质点做匀速直线运动

B.质点做匀加速直线运动

C.质点做加速度逐渐增大的加速运动

D.质点做加速度逐渐减小的加速运动

答案

从图可知,s与v成正比,即s=kv,k是比例系数(常量),

v=

△s
△t
=
k△v
△t
=ka

显然加速度与速度呈正比,所以质点做加速度逐渐增大的加速运动,故C正确.

故选C

单项选择题 A1/A2型题
阅读理解

Scientific discoveries have changed man’s life a great deal during the past century. First of all, they have greatly improved material well-being in several areas of life. In the field of medicine, cures for life threatening diseases have enabled people to live longer. In communication, the telephone and e-mail have made it possible for us to communicate with anyone in the world without leaving our homes or offices. Advances in transportation allow businessmen to fly across the ocean in the morning and return home the same evening. Space technology has put men on the moon. More efficient ways of using available resources, such as coal and solar power, have been explored.

Scientific discoveries have also changed man’s moral atmosphere. Ethical (伦理的) issues are raised by these discoveries. Should we keep a terminally ill person alive through drugs and machines or should we allow him to die in dignity? With advances in transportation had come the problem of pollution for nearly every major city in the world. If cities become uninhabitable, then such technical advances may come with too great a price to pay. Many people also question the wisdom of sending men to the moon when there are urgent problems that have not been solved on earth. During future years, increasing attention must be given to the moral as well as the practical applications of science.

小题1:Scientific discoveries have improved man’s life in several fields. Which of the following is not mentioned in the passage?

A.medicine

B.communication and transportation

C.education

D.space technology小题2: Which of the following statements is true according to the passage?

A.Scientific discoveries have only changed man’s moral atmosphere.

B.Scientific discoveries have only changed man’s material well-being.

C.Scientific discoveries have helped people find efficient ways of using available resources.

D.Men are sent to the moon because there are urgent problems that have not been solved on earth.小题3:At the end of the passage the author says that increasing attention must be given to _________.

A.the moral applications of science

B.the practical applications of science

C.urgent problems on the earth

D.both A and B小题4:The best title for the passage is __________.

A.Science discoveries

B.Science and daily life

C.Advances in transportation

D.City pollution