问题 不定项选择

如图所示,在倾角为θ的光滑斜劈P的斜面上有两个用轻质弹簧相连的物块A、B,C为一垂直固定在斜面上的挡板。A、B质量均为m,斜面连同挡板的质量为M,弹簧的劲度系数为k,系统静止于光滑水平面。现开始用一水平恒力F作用于P,(重力加速度为g)下列说法中正确的是

[ ]

A.若F=0,挡板受到B物块的压力为

B.力F较小时A相对于斜面静止,F大于某一数值,A相对于斜面向上滑动

C.若要B离开挡板C,弹簧伸长量需达到

D.若且保持两物块与斜劈共同运动,弹簧将保持原长

答案

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Moving in with a boyfriend causes women to eat more unhealthily and put on weight. But the opposite is true for men, whose long-term health benefits when they move in with a female partner.

Dieticians at Newcastle University said both partners try to please one another, and so change their dietary habits to suit their other half.

It leads men to eat more light meals, such as salads, fruit and vegetables, while women choose to make creamier, heavier dishes curry or rich pasta sauces, which may please their partner.

Women still have the strongest long-term influence over the couple’s diet and lifestyle, as they still have the traditional role of shopper and cook in most households.

The report, by Newcastle University’s Human Nutrition Research Centre, reviewed the finding of a variety of research projects from the UK, North America and Australia, which looked at the eating and lifestyle habits of couples.

The research shows that women are more likely to put on weight and increase their consumption of foods high in fat and sugar when they move in with their partner.

Women also use food as a comfort when dealing with emotional stress and have been found to gain weight when a relationship ends, while the same finding has not been observed in men.

Many couples reported food as being central to their partnership, and eating together in the evening was particularly important to many.

Report author and registered dietician Dr. Amelia Lake said, “The research has shown that your partner is a strong influence on lifestyle and people who are trying to live healthier lives should take this factor into consideration.”

41. According to the passage, moving in with a girlfriend, men _______.

A. have few changes of their dietary habits

B. have to eat more unhealthy foods

C. don’t like foods high in fat and sugar at all

D. try to eat foods that their girlfriends like

42. The underlined word “light”(in Paragraph 4 ) probably means ________.

A. not very heavy

B. less in fat and sugar

C. gentle

D. not serious or important

43. According to the report by Newcastle University’s Human Nutrition Research Centre, ________.

A. women put on weight only because they want to suit their other half

B. when men are faced with emotional stress, they will change their dietary habits

C. eating together in the evening is a good way to communicate for couples

D. it is wrong to change your dietary habits to suit your partner

44. From the passage, we can infer that _________.

A. women should pay more attention to their partner’s influence on them

B. more men will play roles of shopper and cook in most households

C. couples will not change their dietary habits and lifestyle to please their partner

D. long-term health of men benefits when they move in with a female partner

45. What would be the best title for the passage?

A. Don’t be silly any more, women!

B. Which are better dietary habits?

C. Boyfriends make you fat

D. Dr. Amelia Lake and his study

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