问题 选择题

下列现象中属于内能转化为机械能的是(  )

A.用力划火柴,火柴点燃

B.内燃机的做功冲程

C.锯子锯木头,锯条发热

D.烧红的铁块慢慢被冷却

答案

A、用力划火柴,火柴点燃,是一种摩擦生热,是机械能转化为内能,不符合题意.

B、内燃机正在工作,压缩冲程是机械能转化为内能,内能增大,温度升高,达到燃油的着火点,燃料燃烧,产生高温高压的燃气,具有很大的内能,推动活塞做功,内能转化为机械能,符合题意.

C、锯子锯木头,锯条发热,是一种摩擦生热,是机械能转化为内能,不符合题意.

D、烧红的铁块慢慢被冷却,是铁块和空气存在温度差,发生的热传递,是内能的转移,不符合题意.

故选B.

阅读理解

Cameron thought of himself as merely organized.He certainly did not consider that he took great pains over anything ,he did just enough to get it right.Exactly right, of course as he was fond of telling his staff, “if it’s not exactly right, it’s wrong”.Occasionally a worker might be sad on hearing these words, because it meant another hour or so of going over the same bit of work, correcting the mistakes which Cameron had patiently pointed out.And doing the corrections exactly right of course.

Strangely enough ,his department had the reputation for performing the highest quality work in the company ,and it was seen, and not only by those who worked in the department ,as a sort of elite(出类拔萃)unit.Those programs that had to work first time, straight out of the box, Cameron’s men got those.“It’s mission(任务)critical—give it to Cameron” was almost a catch—phrase with his team.

It helped that Cameron was not merely particular about things.He wanted things done just so ,not because of a personal taste ,but because he had discovered through patient experimentation that this was the best way for it to be done.

小题1:Cameron was a            

A.software programmer

B.a chief scientist

C.quality controller

D.head of department小题2:“Mission-critical” work given to Cameron because       

A.Cameron’s work was error—free

B.Cameron was critical

C.he didn’t mind working late

D.he had a good team小题3:Working for Cameron, people felt that          

A.they were part of an elite

B.their mission was critical

C.Cameron was very particular about things

D.Cameron was patient and responsible小题4:According to the underlined part in paragraph 5,what is meant by someone “who couldn’t cut it”?

A.He didn’t cut corners.

B.He wasn’t good enough.

C.He had the wrong measurements.

D.He was a perfection.小题5:What can we learn about Cameron?

A.He never got things Wrong.

B.He didn’t allow for any mistake.

C.He encouraged work to be done in office hours.

D.He was often misunderstood.小题6:The attitude of the author towards Cameron is that of being       

A.positive

B.sympathetic

C.non-subjective

D.optimistic

单项选择题