(1)某同学利用如图1(a)装置做“探究弹簧弹力大小与长度的关系”的实验. ①在

题型:问答题

问题:

(1)某同学利用如图1(a)装置做“探究弹簧弹力大小与长度的关系”的实验.

①在安装刻度尺时,必须使刻度尺保持______状态.

②他通过实验得到如图1(b)所示的弹力大小F与弹簧长度x的关系图线.由此图线可得该弹簧的原长x0=______cm,劲度系数k=______N/m.

③他又利用本实验原理把该弹簧做成一把弹簧秤,当弹簧秤上的示数如图1(c)所示时,该弹簧的长度x=______cm.

(2)①某同学设计了一个探究无轮子小车的加速度a与小车所受拉力F关系的实验,图2甲为实验装置简图.他想用钩码的重力表示小车受到的合外力,为了减小这种做法带来的实验误差,你认为下列说法正确的是______

A.实验时要平衡摩擦力B.实验时不需要平衡摩擦力

C.钩码的重力要远小于小车的总重力 D.实验进行时应先释放小车再接通电源

②如图2乙所示是某次实验中得到的一条纸带,其中A、B、C、D、E是计数点,相邻计数点间的时间间隔为T,距离如图所示.则打C点时小车的速度为______;该同学计算小车加速度的表达式为______.

③保持实验小车重量20N不变,长木板水平放置,改变砂和砂桶质量,得到图2丙中的图线不通过原点.现在要让图线过原点,则长木板与水平桌面的倾角θ应调整为______.

考点:实验:探究弹力与弹簧伸长的关系
题型:问答题

There was once a farmer who had a fine orchard (果园). He worked very hard all his life and the orchard always did well. But he knew that his three sons looked down upon farm work, and were only interested in getting rich quickly.

When the farmer was old and knew he was going to die, he called his three sons to him and said, “My sons, there’s a lot of gold hidden in the orchard. Dig for it, if you want to have it.” The sons tried to get him to tell them the exact place where the gold was hidden, but he said nothing more.

After the farmer was dead, the sons went to look for the gold. Since they didn’t know where the hiding-place was, they decided to begin digging all over the orchard, They dug and dug, but no gold was found. Finally they had to give up the attempt.

The next summer, the fruit crop was the biggest they had ever had. This was because of the thorough digging the orchard had got.

When the three sons saw the great amount of money they got after they sold the fruit, they suddenly understood what their wise father had meant when he said “There’s gold hidden in the orchard. Dig for it.”

72. When the old farmer was living, ____________.

A. the orchard gave rich crops each year

B. the orchard gave rich crops only when the weather conditions were good

C. the orchard had an average crop      

D. the fruit crop was usually poor

73. Which of the following statements is true?

A. The farmer’s sons were lazy and had never worked on the farm             

B. The farmer’s sons did a lot of buying and selling in town so as to get rich quickly.

C. The farmer’s sons loved farm work, because their father, who was hardworking all his life, had told them to work hard.              

D. The farmer’s sons considered farm work worthless.

74. When the sons asked their father to tell them the exact place where the gold was hidden, he told them nothing, because _________.

A. he was dying           

B. he thought they understood what he meant

C. he wanted them to dig the orchard all over        

D. the gold could easily be found

75. No gold was found because ___________.

A. the farmer’s sons hadn’t dug the orchard deep enough

B. the gold had been stolen

C. the farmer’s sons didn’t know in what part of the orchard the gold was hidden.

D. there was no gold hidden in the orchard.

题型:问答题

治疗中气下陷证,脱肛、胃下垂、子宫脱垂应首选

A.蝉蜕、升麻
B.升麻、葛根
C.葛根、柴胡
D.柴胡、升麻
E.柴胡、蝉蜕

题型:问答题

婴儿生后2~3个月时红细胞数降至3.0×1012/L,血红蛋白量降至110g/L是

A.极重度贫血
B.中度贫血
C.生理性贫血
D.重度贫血
E.轻度贫血

题型:问答题

地震勘探测网布设的基本原则是什么?

题型:问答题

人感染H7N9禽甲型流感病毒除感染禽外,还可感染人、猪、马、水貂和海洋哺乳动物。

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