问题 填空题

班级里组织登楼比赛活动,比一比谁登楼的功率最大.

(1)在活动中必须测量的物理量有:______、______.

(2)所需要的测量工具有:______、______.

(3)计算登楼功率的表达式为P=______.

答案

人登楼时所做得功为:W=Gh=mgh

登楼的功率 P=

W
t
=
Gh
t
=
mgh
t

所以,需要测量的物理量是:人的质量、楼高和登楼的时间,地面到楼高度h相同,因此只需测人的质量m、从地面登上楼的时间t两项.

测量人的质量用磅秤,测量时间用秒表.

故答案为:

(1)人的质量m,登楼的时间t

(2)磅秤,秒表

(3)P=

mgh
t

填空题

请用下列单词或短语的适当形式填空.(有多余选项)

satisfy,   supply,    lead,     would rather ,     struggle,     whatever,     confuse,      work,     rid,                   sunburn,       prefer to,       certain

     There was an old goat that grew a lot of cabbages. He gathered in all his cabbages with the

help of two rabbits. Then he gave each of them ten cabbages to express his thanks. But the goat

got   1 when he found that one of them was very happy while the other was not that happy. So the

goat asked him, "You are not     2 with this?"

     "No, no. Thank you very much for the cabbages. But if I have a choice I would   3 choose

something else," said the rabbit.

     "Ok, you can choose   4 you like from what I have."

    "I wonder if you can teach me to grow cabbages," the rabbit said. "I often can't get enough food

to eat. If I want to    5 a good life, I must grow something of my own. So, I    6 learn to work the

land from you than just accept your cabbages."

     "  7 the land is not that easy. In spring, you must   8   the land of grass; in summer, your skin will

be    9 working in the field and in autumn, you must   10 against bad weather to get in your crops.

Did you really decide to do so?" the goat asked.

     "Yes. I've made up my mind."

     "Ok!"

     With the help of the goat, one year later, the rabbit got a lot of cabbages of his own.

单项选择题