题干

物理兴趣小组制作了如图甲所示的测量大气压强装置,其中弹簧的伸长长度(△L)跟所受拉力(F)的关系如图乙所示,注射器的最大刻度为20ml,全部刻度的长度为20cm,电源电压为6V,电阻R0的阻值为5Ω,电阻R是长20cm、阻值20Ω的均匀电阻丝,电压表的量程为0﹣3V.该气压计使用前先将注射器活塞推到顶端排尽注射器内的空气,并用橡皮帽将注射器孔封闭。

上一题 下一题 0.0难度 选择题 更新时间:2019-03-07 11:02:03

答案(点此获取答案解析)

同类题1

任务型阅读

    Do you know what a big dream is? Does a big dream show one's future? Or, is a big dream something that provides only entertainment? Children dream big dreams, but there are three barriers to realizing dreams____

The self

    Immediately following the birth of a big dream, a negative self-talk takes over and gives all the reasons why it cannot happen. This voice inside of people is the ego(自我).It's there for protecting and should be listened to. Sometimes it is right, but more often it is wrong____ That's why only a handful of people make their dream come true

Family and friends

    Family and friends are a lot the ego.____ so they will often list all the reasons why the big dreams won't come true. Sometimes, family and friends destroy dreams of those they love most, out of their own fear of those left behind.

____

    If one gets past the first two barriers, one has to face the world. It is the last and the most terrible barrier. In the past, big dreamers were locked up and sometimes even killed when they were shown to the world. Fortunately, in most of the world today, big dreamers just get laughed at ____When children feel confident and then try their best, they will be ready to accept any failure. The truth is that every great dreamer whose dreams have never seen the light of success knows failure well. They simply fail until they succeed

A. The world

B. The future

C. Most people are influenced by it

D. They want to protect those they love

E. And their big dream is to be a rock star or a famous artist

F. They often kill them before they ever have a chance to grow

G. The way to realize a big dream is with confidence and action