问题 填空题

2005年10月12日9时,运载“神六”飞船的火箭点火升空,腾飞的火箭相对于______是运动的;飞船在太空中通过喷气来实现变轨(改变运行高度、方向),这是因为______;飞船降落时,返回舱与大气剧烈摩擦,表面温度急剧升高,这是机械能转变为______能.

答案

腾飞的火箭以地面为参照物是运动的,因为火箭相对地面的位置在发生变化;

飞船之所以在太空中能够实现变轨,原因是由于受到了力的作用,因为力是改变物体运动状态的原因,而它受到的力来自于反作用力,这是因为物体间力的作用是相互的;

飞船降落时,返回舱与大气剧烈摩擦,摩擦要生热,发生的能量转化是机械能转化为热能.

故答案为:地面或地面上的物体,力可以改变物体的运动状态、物体间力的作用是相互的,热.

判断题
单项选择题

Jan Hendrik Schon’s success seemed too good to be true, and it was. In only four years as a physicist at Bell Laboratories, Schon, 32, had co-authored 90 scientific papers—one every 16 days—detailing new discoveries in superconductivity, lasers, nanotechnology and quantum physics. This output astonished his colleagues, and made them suspicious. When one co-worker noticed that the same table of data appeared in two separate papers—which also happened to appear in the two most prestigious scientific journals in the world, Science and Nature—the jig was up. In October 2002, a Bell Labs investigation found that Schon had falsified and fabricated data. His career as a scientist was finished. Scientific scandals, which are as old as science itself, tend to follow similar patterns of presumption and due reward.

In recent years, of course, the pressure on scientists to publish in the top journals has increased, making the journals much more crucial to career success. The questions are whether Nature and Science have become too powerful as arbiters of what science reaches to the public, and whether the journals are up to their task as gatekeepers.

Each scientific specialty has its own set of journals. Physicists have Physical Review Letters, neuroscientists have Neuron, and so forth. Science and Nature, though, are the only two major journals that cover the gamut of scientific disciplines, from meteorology and zoology to quantum physics and chemistry. As a result, journalists look to them each week for the cream of the crop of new science papers. And scientists look to the journals in part to reach journalists. Why do they care Competition for grants has gotten so fierce that scientists have sought popular renown to gain an edge over their rivals. Publication in specialized journals will win the acclaims from academics and satisfy the publish-or-perish imperative, but Science and Nature come with the added bonus of potentially getting your paper written up in The New York Times and other publications.

Scientists tend to pay more attention to the big two than to other journals. When more scientists know about a particular paper, they’re more apt to cite it in their own papers. Being oft-cited will increase a scientist’s "Impact Factor", a measure of how often papers are cited by peers. Funding agencies use the "Impact Factor" as a rough measure of the influence of scientists they’re considering supporting.

According to the passage, what makes Science and Nature powerful().

A. They cover the best researches on a variety of subjects.

B. They publish controversial papers that others won’t.

C. They prefer papers on highly specialized research.

D. They have a special system of peer-review.