问题 选择题

关于物体惯性,下面说法中正确的是(  )

A.物体不受力时,运动状态保持不变的特性叫做惯性

B.物体只有在静止或匀速直线运动时,才具有惯性

C.物体的速度越快,其惯性越大

D.物体的惯性与它的运动状态、受力情况毫无关系

答案

一切物体都有惯性,惯性只与质量有关,与其它因素均无关,故ABC错误,D正确.

故选D.

单项选择题

Although there are many skillful Braille readers, thousands of other blind people find it difficult to learn that system. They are thereby shut (1) from the world of books and newspapers, having to (2) on friends to read aloud to them.

A young scientist named Raymond Kurzweil has now designed a computer which is a major (3) in providing aid to the (4) .His machine, Cyclops, has a camera that (5) any page, interprets the print into sounds, and then delivers them orally in a robot-like (6) through a speaker. By pressing the appropriate buttons (7) Cyclops’s keyboard, a blind person can "read" any (8) document in the English language.

This remarkable invention represents a tremendous (9) forward in the education of the handicapped. At present, Cyclops costs $ 50,000. (10) , Mr. Kurzweil and his associates are preparing a smaller (11) improved version that will sell (12) less than half that price. Within a few years, Kurzweil (13) the price range will be low enough for every school and library to (14) one. Michael Hingson, Director of the National Federation for the Blind, hopes that (15) will be able to buy home (16) of Cyclops for the price of a good television set.

Mr. Hingson’s organization purchased five machines and is now testing them in Maryland, Colorado, Iowa, California, and New York. Blind people have been (17) in those tests, making lots of (18) suggestions to the engineers who helped to produce Cyclops.

"This is the first time that blind people have ever done individual studies (19) a product was put on the market," Hingson said. "Most manufacturers believed that having the blind help the blind was like telling disabled people to teach other disabled people. In that (20) , the manufacturers have been the blind ones.

8()

A.visual

B.printed

C.virtual

D.spoken

判断题