问题 实验题

小红猜想动能的大小可能与物体质量和运动速度有关,于是设计了如图甲、乙所示的实验,探究动能的大小与哪些因素有关。

 

        让质量相同的两个小球沿同一光滑斜面分别从A处和B处开始向下运动,然后与放在水平面上的纸盒相碰,纸盒在水平面上移动一段距离后静止,如图甲所示。

        让不同质量的两个小球沿同一光滑斜面分别从B处开始向下运动,然后与放在水平面上的纸盒相碰,纸盒在水平面上移动一段距离后静止,如图乙所示。

        上述甲、乙两组实验中:

(1)乙图中让不同质量的两个小球从同一高度滚下的目的是两球到达水平面时,具有相同的

                       。

(2)选用图甲探究的是动能与                    的关系,理由是:两球                  相等;得出的结论是:_____________________。

(3)选用图乙探究的是动能与                   的关系,得出的结论是:                                                    

(4)物理研究方法有许多,如等效替代法、类比法、对比法、控制变量法;本实验中运用了两种研究方法,一是                  法;二是转换法,就是用纸盒移动的距离长短来表示小球动能的大小。

答案

(1)速度

(2)速度;质量;当质量一定时,速度越大动能越大

(3)质量;当速度一定时,质量越大动能越大

(4)控制变量

完形填空

There once was a master who went to India. He had never been there before. When he got there, he saw a lot of f 小题1: . In India they have plenty of fruit to sell, but much of it is expensive b 小题2:  they can’t grow much as a result of the water situation. He saw a big basket of some very red, long fruit. And it was the c 小题3:  in the shop, not expensive at all.

He went up and asked,“how much per kilo?”“Two rupees.”Two rupees in India is almost

n 小题4: ; it’s like dirt (尘土). So he bought a whole kilogram of it and started eating it. But

a 小题5:  he ate some of it: Oh, my god! His eyes watered, his mouth watered and burned, his eyes were burning, his head was burning and his face became red. He jumped up and down, saying,“Ah! Ah! Ah!”

But he s 小题6:  continued to eat! Some people looking at him shook their heads and said,“You’re crazy. Those are chilies (辣椒)! You can’t eat them like that. They’re not fruit!” However, the master said, “No, I can’t stop! I paid money for them, and now I’ll eat them. It’s my money!”

You may think that master was s 小题7: , right? Similarly, we sometimes do a lot of things

l 小题8:  that. We devote money, time or effort to a relationship. Even though the suffering experience tells us it won’t w 小题9: , and we know there’s no hope things will change in the future—we still continue just because we’ve devoted money, time, effort and love to it. Just like the man who ate the chilies and suffered so much but couldn’t stop.

So even if you’ve lost something, let it g 小题10:  and move on. That’s better than continuing to lose.

单项选择题