不考虑人克服自身重力做功,我们把重100N的物体从地面上提起并把它举高到2m高的

题型:填空题

问题:

不考虑人克服自身重力做功,我们把重100N的物体从地面上提起并把它举高到2m高的地方,我们对重物做了            J的功。如果人依然站在地面上,改用动滑轮来完成这件事,那么,我们在完成必须对重物做的             J的功外,我们还不得不克服动滑轮的          以及滑轮与轴、绳子与滑轮之间的             来做功。从完成任务的角度看,我们直接对重物所做的功是有用的,物理学就称这种功为           功。因为使用机械而导致的不得不做的功,其实不是我们做的目的所在,物理学把这部分功称为            功,也叫           功。

考点:功的计算有用功和额外功
题型:填空题

阅读下面短文。在短文的空格内填入适当的词,使其内容通顺。(每空格限填一词)

There was once a rich man who loved his little boy very

much. He wanted to try his best to please (使……高兴) him.

So he gave him a horse to ride, beautiful rooms to live in,

pictures, books, toys and everything that money  小题1: buy.

But for all this, the little boy was still  小题2: . He wore a frown ( 皱眉 ) wherever he went, and always wished for something he did not have. The man didn' t know how to make his son happy.

One day, a magician (魔术师) came to the man and said to him, "I can make your son happy and turn his frowns into smiles, but you must pay me a great price for 小题3: him the secret. "

"All right," said the man, "No matter what you ask for, I’ll give you." The magician took the boy into a secret room. He wrote something on a piece of paper, and then gave it to the   小题4:There on the paper came the words, "Do one kind thing for someone every day. " The boy  小题5: the advice and became one of the happiest boys.

Only those who stop thinking about their own happiness can be truly happy.

题型:填空题

平面内有5个点,每两个点都用直线连接起来,则最多可得______条直线,最少可得______条直线.

题型:填空题

石砌驳岸工程内容包括()

A、石料加工

B、砌石

C、勾缝

D、上彩

题型:填空题

下列关于控制燃烧过程“三T”的目的的论述正确的是( )。

A.燃料燃烧完全
B.氧的利用率最高
C.反应速度最快
D.燃烧室的设计体积最小

题型:填空题

绿色施工评价时按()等三个阶段进行。

A.设计阶段

B.地基与基础工程

C.结构工程

D.装饰装修与机电安装工程

E.施工阶段

更多题库