When asteroids collide, some collisions cause an asteroid to spin faster; others slow it down. If asteroids are all monoliths—singlerocks—undergoing random collisions, a graph of their rotation rates should show a bell-shaped distribution with statistical “tails” of very fast and very slow rotators. If asteroids are rubble piles, however, the tail representing the very fast rotators would be missing,because any loose aggregate spinning faster than once every few hours(depending on the asteroid’s bulk density) would fly apart. Researchers have discovered that all but five observed asteroids obey a strict limit on rate of rotation.The exceptions are all smaller than 200 meters in diameter, with an abrupt cutoff for asteroids larger than that.
The evident conclusion—that asteroids larger than 200 meters across are multicomponent structures or rubble piles—agrees with recent computer modeling of collisions, which also finds a transition at that diameter. A collision can blast a large asteroid to bits, but after the collision those bits will usually move slower than their mutual escape velocity. Over several hours, gravity will reassemble all but the fastest pieces into a rubble pile. Because collisions among asteroids are relatively frequent, most large bodies have already suffered this fate. Conversely, most small asteroids should be monolithic, because impact fragments easily escape their feeble gravity.
The discovery of which of the following would call into question the conclusion mentioned in the highlighted text?
An asteroid 100 meters in diameter rotating at a rate of once per week
An asteroid 150 meters in diameter rotating at a rate of 20 times per hour
An asteroid 250 meters in diameter rotating at a rate of once per week
An asteroid 500 meters in diameter rotating at a rate of once per hour
An asteroid 1,000 meters in diameter rotating at a rate of once every 24 hours
题目分析:
文章推断题:以下哪个发现会质疑高亮的结论?
高亮部分:直径比200米大的行星是多成分结构,或者是rubber pile的。
选项分析:
A选项:直径100米的行星一周旋转一次:直径比200米的行星如何,与这个结论无关。
B选项:直径150米的行星一小时转20次:同A。
C选项:直径250米的行星一周转一次:转得很慢,与结论一致。无法起到质疑的作用。
D选项:正确。直径500米的行星一小时转一次:正确。直径比200米的行星转得很快,质疑了结论。
E选项:直径1000米的行星每24小时转一次:文章定义大约每几个小时转一次的行星是快的,所以每24小时转一次是慢的,符合结论。
难死了难死了
考场上碰到这题是喜还是祸!!哈哈
看懂了文章,没做对...
细节题,找定位!
原文定位在第三句:If asteroids are rubble piles, however, the tail representing the very fast rotators would be missing,because any loose aggregate spinning faster than 【once every few hours】(depending on the asteroid’s bulk density) would fly apart
提亮内容是:asteroids larger than 200 meters across are multicomponent structures or rubble piles
即 larger than 200 meters --> multicomponent structure / rubble piles
要question这个结论个人的想法是
大于200 但不是multicomponent structure / rubble piles
小于200 但是是multicomponent structure / rubble piles
但是发现选项都是大小和配速,所以破题点是找出不符合文章描述的大小、速度匹配的 —— 200meters 配速是 once every few hours以内,超出的不存在。
文章很tricky的是关于配速的描述faster than once every few hours(depending on the asteroid’s bulk density) would fly apart——这里的depending不是指其他density下会有其他速度,而是说由density决定
If asteroids are rubble piles,however, the tail representing the very fast rotators would be missing,because any loose aggregate spinning faster than once every few hours would fly apart. 如果比几小时转一次的速度快,就会飞走。所以rubble piles不会飞走 ➡️ 速度要小于几小时一次
any loose aggregate spinning faster than once every few hours转的快的就会分解,而只有大于200的才会分解。大的又转的快的就是D
转速要快 打错
If asteroids are rubble piles, however, the tail representing the very fast rotators would be missing,because any loose aggregate spinning faster than once every few hours(depending on the asteroid’s bulk density) would fly apart
转速低于几小时一次,必须是rubble piles
1)any loose aggregate spinning faster than once every few hours would fly apart 2)asteroids larger than 200 meters across are multicomponent structures or rubble piles
结合起来也就是rubble piles必须同时满足两个条件:1)转速必须低于几小时一次 2)大于200米以上。选项中任意一个条件不符合就可以质疑
because any loose aggregate spinning faster than once every few hours(depending on the asteroid’s bulk density) would fly apart.
A 原文讨论的是直径大于200的,无关
B 原文讨论的是直径大于200的,无关
C 一周一次,是慢的,加强
D 一小时一次,是快的,削弱,正确
E 24小时一次,是慢的,加强
解题思路:注意题干当中的call into question,定位在第二段红色高亮的部分。原始逻辑是:”rubble piles不会特别快,所以直径大于200的是rubble piles”
all but 除了。。。
不知道对不对,推理如下:
这个明显的结论——大于200的都是rubble的原因是,大于200的rubble如果旋转速度超过数小时一次,比如每小时一次,就会裂解,因为他是loose的,那么这个和后面的research的结论一致了,就是大于200的rubble都不会有高速带,只有小于200的才有高速带。
削弱就是有任何一个反例的存在,比如500的(大于200)以转速每小时一次(速度超过数小时一次)存在着——C
还是前面那两个 if 句子 没读懂 读懂很简单
不知道对不对,推理如下:
这个明显的结论——大于200的都是rubble的原因是,大于200的rubble如果旋转速度超过数小时一次,比如每小时一次,就会裂解,因为他是loose的,那么这个和后面的research的结论一致了,就是大于200的rubble都不会有高速带,只有小于200的才有高速带。
削弱就是有任何一个反例的存在,比如500的(大于200)以转速每小时一次(速度超过数小时一次)存在着——C
mark
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就像cr的weaken题。这里只要找出直径大于200的asteroid 旋转的还特别快的就行。
1.直接排除ab
2.忽略大小 直接看转速 c 一周一次 d 一个小时一次 e 一天一次,那就选d最具有说服力可以weaken
Over several hours, gravity will reassemble all but the fastest pieces into a rubble pile. 每小时换一次速度,就聚集不了了。
Researchers have discovered that all but five observed asteroids obey a strict limit on rate of rotation---只有5个被观察的小星星例外(速度不被限制,也就说说可快可慢),其余的都在速度上有限制,那么对于大的来说应该转的慢。选项中后三个都是在说大于200米直径的,旋转速度最快的质疑了高亮部分。本题解题应该结合上文,在理解基础上进行推断。
找不到这个问题的信息点,哪里可以推出选项?
在这里:because any loose aggregate spinning faster than once every few hours(depending on the asteroid’s bulk density) would fly apart. 速度快于几小时1次的都会脱离
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