一箱土豆在转盘上随转盘以角速度ω做匀速圆周运动,其中一个处于中间位置的土豆质量为

题型:选择题

问题:

一箱土豆在转盘上随转盘以角速度ω做匀速圆周运动,其中一个处于中间位置的土豆质量为m,它到转轴的距离为R,则其他土豆对该土豆的作用力为

A.mg

B.mω2R

C.

D.

考点:向心力
题型:选择题

低温巴氏消毒条件是30min,温度为

A.56~65℃
B.62~65℃
C.65~85℃
D.85~90℃
E.90~96℃

题型:选择题

阅读理解。

     A research shows that expressions on our faces have a strong relationship with our genes (基因).

According to the study, facial expressions of our feelings are innate and are not achieved in cultural

learning.

     This is the first research to show that blind people have the same facial expressions as the sighted

when showing certain feelings-the same facial muscles (肌肉) start working. What's more, the research

gives the new method of how people control their feelings in certain social situations. It states that people

do not leam to manage their facial expressions by examining the expressions of others.

     In his study, David Matsumoto, San Francisco State University Psychology Professor, examined

facial expressions of bhnd and sighted judo athletes (柔员) that took part in the Summer Olympics and

Paralympics (残奥会). He examined over 4 800 pictures of different athletes who came from 23 countries.

Matsumoto found that both blind and sighted sportsmen had the same facial expressions, according to a

specific social situation.

     "This suggests genes decide facial expressions of feelings," he said.

     One of his findings was the "social smiles" of judo athletes who lost their match and got the second

place. It is interesting to find that only mouth muscles are used in social smiles, while during real smiles,

shown when a person is really happy, the eyes of a person twinkle and get smaller and the cheeks (脸颊)

rise.

     "Losers pu8hed their lower lip up as if to control the feeling on their face and many produced social

smiles," said Matsumoto. "People blind from birth were unable to leam to manage their feelings with the

help of examining others' facial expressions." He thought that there must be another system involved.

     "It's possible that in order to hide sad feelings, humans have developed a system that closes the mouth

so that they are stopped from crying, biting or rudeness," he said.

1. The underlined word "innate" in the first paragraph means _____.

A. from birth

B. from daily life

C. from others

D. from teaching

2. According to the passage, real smiles are different from social smiles in _____.

A. opening the eyes

B. using facial muscles

C. closing the mouth

D. watching others' expressions

3. How does the writer make us believe the new findings?

A. By telling us an interesting story.

B. By interviewing some researchers.

C. By showing the results of the research.

D. By giving the answers to the questions.

4. Which can be the best title for the passage?

A. Smiles and Olympics

B. Blind and Sighted Athletes

C. Social Smiles and Real Smiles

D. Genes and Facial Expressions

题型:选择题

对于垂体瘤下列哪项不正确()

A.无功能垂体瘤不分泌具有生物学活性的激素

B.无功能垂体瘤和促性腺激素瘤均为大腺瘤

C.垂体瘤的诊断主要采用影像技术

D.有功能垂体瘤可表现为占位病变和激素分泌异常

E.垂体PRL瘤首选手术治疗

题型:选择题

金本位制下汇价决定的基本依据是()

A.货币的对内价值

B.物价水平

C.铸币平价

D.货币政策

题型:选择题

根据游客在生活中的表现,其人格类型有以下几个方面()。

A.正常的游客

B.使人难堪的游客

C.依赖性的游客

D.喜欢交际的游客

E.神经质的游客

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