Questions 11-15People value money desperately because they value one another desperately; thus the cause of panic in the stock-market plunge is not that people will lose their dollars but that they will lose their sense of community. For the past couple of weeks, the nation has watched itself roll toward ruin because people were losing their money in bales. If one were tasteless enough to ask a big loser what exactly he was losing, he would sputter, "What am I losing My car! My beautiful home! My children’s educations! My clothes! My dinner! My dollars!" They are all true. People have been mourning the passing of their money for all the things that money can do, and what money can do is impressive. Money can build cities, cure diseases, and win wars. The sudden acquisition of the stuff can toss our spirits into the air like a hat.Money can do considerably more. It offers power, an almost unique form of power, not simply because it allows us to acquire and possess things but because it is we who determine its worth; we who say a ruby costs more than an apple; we who decide that a tennis court is more valuable than a book. Paradoxically, money creates a deep sense of powerlessness as well, since technically we cannot provide money for ourselves; someone or something else must do that for us-our employers or, until recently, our stocks. All that, money can do: and when such essential, familiar functions are snatched from one’s life, small wonder that people may grow wild, frantic, and even murderous.What money can do, however, is not the same as what money is. Let’s return for a moment to the theory: people value money because they value one another. In other words, the usefulness of money is directly related to and established by continuous mutual need. People work for money to buy things that other people make or do, things that they cannot or will not make or do for themselves but that they deem necessary for some definition of self-improvement.Abstractly, money is one of the ways, indeed a universally accepted way, by which we make connections. Cash is cold. So the connections may feel cold, but real blood flows through them. These connections constitute one of the central means by which societies cohere; by which they sustain and characterize themselves.When the coin begins to wobble, as it has in the past weeks, a fear seizes the mind that is disorienting. The fear is not merely that of the loss of possessions but of self-possession, which in some sense is bought and sold from person to person in infinite daily bargains. To lose money is frightening. To lose touch with others is more frightening still. Losing touch may cause the panic of the times.
Under what circumstances are connections related to cash said to be cold in the passage
A．When they are not established for societies to cohere.
B．When they are not compared to "real blood".
C．When their functions are snatched from people’s life.
D．When their worth is hard to determine and not valued.
验证机械能是否守恒，他采用较好的装置进行实验，得到如图丙所示的一条完整纸带，将纸带上打出的第一个点标为A点，第二个点标为B点，后面依次类推，分别标为C、D、E、F、G、H、I，则在D点时重物运动的速度大小为 m/s。（计算结果保留两位有效数字）
可知重物速度的大小vB=
=0.91m/s