问题 实验题

在“验证阿基米德原理”的实验中,各实验小组同学选用恰当的器材,分别用图所示的实验方法测量了一些数据,并通过计算记录在表格中。

实验

序号

液体的密度(g/cm3物体浸入液体的体积(cm3浮力(N)物体排开的液体所受重力(N)
11200.20.196
21400.40.392
31600.60.588
41.5200.30.294
51.5400.60.588
61.5600.90.882
(1)分析实验序号1、2、3或4、5、6中前三列的实验数据,可得出的初步结论是

                                                                 

(2)分析实验序号                        中的相关数据可得出的初步结论是:当物体排开液体的体积相同时,液体密度越大,物体受到的浮力越大。

(3)甲小组同学分析了表中最后两列数据及相关条件认为这些实验数据能证明阿基米德原理,即浸在液体中的物体受到向上的浮力,浮力的大小              物体排开的液体所受重力。

(4)乙小组同学发现最后两列数据不相等,于是他们把表格中浮力一列的数据分别改成“0.196;0.392;0.588;0.294;0.588;0.882”,然后也得出了验证了阿基米德原理的结论。你认为乙小组的做法       (选填“正确”或“错误”),理由:                

答案

(1)同种液体,物体受到的浮力与物体排开液体的体积成正比。(2)1、4或2、5或3、6

(3)等于。(4)错误;要尊重实验数据,未经实验不得随意修改实验数据。

题目分析:浸在液体中物体所受的浮力大小与液体的密度和物体排开液体的体积有关,在探究过程中应用的方法是控制变量法。(1)分析实验序号1、2、3或4、5、6中前三列的实验数据,可得出的初步结论是同种液体,物体受到的浮力与物体排开液体的体积成正比。(2)在探究浮力大小与液体密度大小的关系时,应控制排开液体的体积相同,故选1、4或2、5或3、6。(3)由表中数据分析可知:浮力的大小等于物体排开的液体所受重力。(4)在进行实验过程中,应尊重实验数据,在误差允许范围内不得修改实验数据。故是错误的。

单项选择题

For my proposed journey, the first priority was clearly to start learning Arabic. I have never been a linguist. Though I had traveled widely as a journalist, I had never managed to pick up more than a smattering of phrases in any tongue other than French, and even my French, was laborious for want of lengthy practice. The prospect of tackling one of the notoriously difficult languages at the age of forty, and trying to speak it well, both deterred and excited me. It was perhaps expecting a little too much of a curiously unreceptive part of myself, yet the possibility that I might gain access to a completely alien culture and tradition by this means was enormously pleasing.

I enrolled as a pupil in a small school in the center of the city. It was run by a Mr Beheit, of dapper appearance and explosive temperament, who assured me that after three months of his special treatment I would speak Arabic fluently. Whereupon he drew from his desk a postcard which an old pupil had sent him from somewhere in the Middle East, expressing great gratitude and reporting the astonishment of local Arabs that he could converse with them like a native. It was written in English. Mr Beheit himself spent most of his time coaching businessmen in French, and through the thin, partitioned walls of his school one could hear him bellowing in exasperation at some confused entrepreneur: "Non, M. Jones. Jane suis pas francais. Pas, Pas, Pas!" (No Mr. Jones, I’m NOT French, I’m not, not, NOT!). I was gratified that my own tutor, whose name was Ahmed, was infinitely softer and less public in approach.

For a couple of hours every morning we would face each other across a small table, while we discussed in meticulous detail the colour scheme of the tiny cubicle, the events in the street below and, once a week, the hair-raising progress of a window-cleaner across the wall of the building opposite. In between, hearing in mind the particular interest I had in acquiring Arabic, I would inquire the way to some imaginary oasis, anxiously demand fodder and water for my camels, wonder politely whether the sheikh was prepared to grant me audience now. It was all hard going. I frequently despaired of ever becoming anything like a fluent speaker, though Ahmed assured me that my pronunciation was above average for a Westemer. This, I suspected, was partly flattery, for there are a couple of Arabic sounds which not even a gift for mimicry allowed me to grasp for ages. There were, moreover, vast distinctions of meaning conveyed by subtle sound shifts rarely employed in English. And for me the problem was increased by the need to assimilate a vocabulary, that would vary from place to place across five essentially Arabic-speaking countries that practiced vernaculars of their own: so that the word for "people", for instance, might be nais, sah ’ab or sooken.

Each day I was mentally exhausted by the strain of a morning in school, followed by an afternoon struggling at home with a tape recorder. Yet there was relief in the most elementary forms of understanding and progress. When merely got the drift of a torrent which Ahmed had just released, I was childishly elated. When I managed to roll a complete sentence off my tongue without apparently thinking what I was saying, and it came out right, I beamed like an idiot. And the enjoyment of reading and writing the flowing Arabic script was something that did not leave me once I had mastered it. By the end of June, no-one could have described me as anything like a fluent speaker of Arabic. I was approximately in the position of a fifteen-year old who, equipped with a modicum of schoolroom French, nervously awaits his first trip to Paris. But this was something I could reprove upon in my own time. I bade farewell to Mr Beheit, still struggling to drive the French negative into the still confused mind of Mr Jones.

The word "modicum" in the last paragraph can be replaced by()

A. competence

B. excellence

C. mimicry

D. smattering

填空题