To prevent tsunami-caused disasters, several countries worked together to expand the use of a tsunami-detecting system that had been developed in the United States by the National Oceanic and Atmospheric Administration (NOAA). The system________ of an instrument installed on the seafloor — called a tsunameter — that measures pressure changes caused by a passing tsunami. The tsunameter sends a signal to a surface buoy (浮标), which sends the data to a satellite, which ________ the information to warning centers around the world.
By 2004 only six such detectors had been installed, all in the Pacific. There were________ in the Indian Ocean, and many countries in the region had no national warning centers that could have ________ local communities. That policy mistake had tragic consequences. In Sumatra people had only a few minutes to run, ________the tsunami took two hours to reach India, and some 16,000 people died there. “It was totally unnecessary,” says Paramesh Banerjee, a geo-physicist at Nanyang Technological University in Singapore. “Technically it would have been relatively ________ to install a tsunami warning system for the Indian Ocean.”
There are now 53 detector buoys operating in the world’s oceans, including 6 of a planned 27 in the Indian Ocean. So a (n)________ of the 2004 horror, in which the tsunami traveled for hours and still caught people by ________ is less likely. But buoys would not have helped in Sumatra. People living on coasts near a rupturing fault (地壳断层) can’t wait for ________ that a tsunami is on its way, which it often isn’t; they must flee as soon as the quake hits. The Japanese warning system relies not only on tsunameters but also on seismometers (地震测量仪) — a thousand of them ________ the country, the densest network anywhere — combined with a computer model that forecasts the scale of a tsunami from the magnitude (震级) and ________ of the quake.
In March, the system, which is run by the Japan Meteorological Agency (JMA), did not work perfectly. JMA’s initial ________, while the ground was still shaking, put the quake magnitude at 7.9 — but later analysis revealed a quake that, at magnitude 9, was 12 times larger. The tsunami forecast warned of waves of ten feet or more — but they reached 50 feet in Minanisanriku and in some places even ________. But the human ________ to the warning was imperfect as well. “I think this time many people who lived above the high-water mark of the 1960 tsunami didn’t bother to run.” says Jin Sato, mayor of Minanisanriku. “Many of them died.” The town’s seawall, he thinks, also gave people a false sense of ________
1．| A．approves | B．rids | C．expects | D．consists |
2．| A．broadcasts | B．foresees | C．assigns | D．imposes |
3．| A．some | B．a few | C．none | D．others |
4．| A．qualified | B．alerted | C．substituted | D．fueled |
5．| A．although | B．until | C．as | D．where |
6．| A．difficult | B．thoughtful | C．easy | D．pressing |
7．| A．alternative | B．perspective | C．repetition | D．resume |
8．| A．surprise | B．mistake | C．accident | D．force |
9．| A．reference | B．confirmation | C．suggestion | D．expectation |
10．| A．undertake | B．multiply | C．deposit | D．blanket |
11．| A．location | B．direction | C．territory | D．length |
12．| A．note | B．catalogue | C．volume | D．estimate |
13．| A．worse | B．larger | C．higher | D．wider |
14．| A．schedule | B．scheme | C．monitor | D．response |
15．| A．warning | B．security | C．setting | D．responsibility |
=3m处放置质量与物体A 相等的另一物体B（物体B底面光滑）。在t=0时刻对物体A施加一水平向右的推力F=6N，物体A开始相对长木板滑动，同时给物体B一向右的瞬时初速度
=2m/s，木板与水平地面间的动摩擦因数
=0.05，物体A与木板间的动摩擦因数
=0.4，最大静摩擦力等于滑动摩擦力，取重力加速度大小g=10m/s2，物体A、B均可视为质点。求:
=3s时物体A、B在木板上相撞，木板的长度L；
=2.4s 时撤去推力F，试分析物体A、B能否相撞？若能，求A、B两物体从撤去推力F到相撞所用的时间t；若不能，求A、B两物体从撤去推力F到A、B之间距离达到最小时所用的时间t。
的NaHCO3溶液pH约为8.3，向5 mL 
，
，
，溶液混合后体积变化忽略不计]下列有关说法
、
比值为：
，其平衡常数约为
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