问题 问答题

小军同学通过高倍望远镜观察月亮,发现月面是凸凹不平的,如图所示。这是由于流星在太空中运行到靠近月球时,在月球的引力作用下坠落到月面,与月面发生碰撞而形成的坑洞,叫做月坑。

小军同学猜想月坑的深度可能与流星的质量、体积及下落的高度有关。

于是,他设计了一个用一只铺满厚厚的细沙的盘子和几个不同的小球及刻度尺进行探究月坑深度的模拟实验,如图所示。经过实验,数据记录如下表:

请你分析实验数据,并回答下列问题:

(1)由1、2、3三组数据可得:“月坑”的深度与流星的__________有关。

(2)由_____、_____、______三组数据可得:“月坑”的深度与流星的质量有关。

(3)“月坑”的深度还与流星的体积有关:体积越大,“月坑”的深度__________。

(4)请你结合小军的研究过程就“影响月坑深度的因素”问题提出另外一个猜想:__________________________________。

答案

(1)下落高度

(2)3、6、7

(3)越浅

(4)月坑深度可能和流星的密度有关

单项选择题
单项选择题

It is no longer just dirty blue-collar jobs in manufacturing that are being sucked offshore but also white-collar service jobs, which used to be considered safe from foreign competition. Telecoms charges have tumbled, allowing workers in far-flung locations to be connected cheaply to customers in the developed world. This has made it possible to offshore services that were once non-tradable. Morgan Stanley’s Mr. Roach has been drawing attention to the fact that the "global labour arbitrage" is moving rapidly to the better kinds of jobs. It is no longer just basic data processing and call centres that are being outsourced to low-wage countries, but also software programming, medical diagnostics, engineering design, law, accounting, finance and business consulting. These can now be delivered electronically from anywhere in the world, exposing skilled white-collar workers to greater competition.

The standard retort to such arguments is that outsourcing abroad is too small to matter much. So far fewer than lm American service-sector jobs have been lost to off-shoring. Forrester Research forecasts that by 2015 a total of 3.4m jobs in services will have moved abroad, but that is tiny compared with the 30m jobs destroyed and created in America every year. The trouble is that such studies allow only for the sorts of jobs that are already being off-shored, when in reality the proportion of jobs that can be moved will rise as IT advances and education improves in emerging economies.

Alan Blinder, an economist at Princeton University, believes that most economists are underestimating the disruptive effects of off-shoring, and that in future two to three times as many service jobs will be susceptible to off-shoring as in manufacturing. This would imply that at least 30% of all jobs might be at risk. In practice the number of jobs off-shored to China or India is likely to remain fairly modest. Even so, the mere threat that they could be shifted will depress wages:

Moreover, says Mr. Blinder, education offers no protection. Highly skilled accountants, radiologists or computer programmers now have to compete with electronically delivered competition from abroad, whereas humble taxi drivers, janitors and crane operators remain safe from off-shoring. This may help to explain why the real median wage of American graduates hat fallen by 6% since 2000, a bigger decline than in average wages.

In the 1980s and early 1990s, the pay gap between low-paid, low-skilled workers and high-paid, high-skilled workers widened significantly. But since then, according to a study by David Autor, Lawrence Katz and Melissa Kearney, in America, Britain and Germany workers at the bottom as well as at the top have done better than those in the middle-income ’group. Office cleaning cannot be done by workers in India. It is the easily standardised skilled job in the middle, such as accounting, that are now being squeezed hardest. A study by Bradford Jensen and Lori Kletzer, at the Institute for International Economics in Washington D. C., confirms that workers in tradable services that are exposed to foreign competition tend to be more skilled than workers in non-tradable services and tradable manufacturing industries.

According to the text, Forrester Research Prediction might be different if ()

A. outsourcing abroad is large enough to matter much

B. the proportion of jobs that can be moved will rise

C. more comprehensive factors are taken into account

D. education improvement in emerging economies plays a role