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放在水平桌面上的杯子，质量为0.2kg，容积为5×10﹣4m3，然后装满水，其水的重力为　 　N，总重力　　 N，若杯子与桌面的接触面积为 5×10﹣2m2，则杯子对桌面的压强为　Pa．

答案

4.9；6.86；137.2．

题目分析：由题意知杯子的质量m=0.2kg，g=9.8N/kg，则重力G杯=mg=0.2kg×9.8N/kg=1.96N；水的体积V=5×10﹣4m3，密度ρ=1×103kg/m3，则水的重力G水=m水g=ρVg=1×103kg/m3×9.8N/kg×5×10﹣4m3=4.9N，总重力G=G杯+G水=1.96N+4.9N=6.86N；而杯子对桌面的压力F=G=6.86N，受力面积S=5×10﹣2m2，则杯子对桌面的压强。

读图填空题

下图为人体血液循环模式图，据图分析回答：

（1）用图中数字表示肺循环的途径：                              该循环的生理功能是                               。

（2）体循环与肺循环是通过哪种器官联系在一起的              。

（3）体循环起始于[   ]                该循环的生理作是                                          。

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单项选择题

WLANs are increasingly popular because they enable cost-effective connections among people, applications and data that were not possible, or not cost-effective, in the past. For example, WLAN-based applications can enable fine-grained management of supply and distribution (166) to improve their efficienty and reduce (167) . WLANs can also enable entirely new business processes. To cite but one example, hospitals are using WLAN-enabled point-of-care applications to reduce errors and improve overall (168) care. WLAN management solutions provide a variety of other benefits that can be substantial but difficult to measure. For example, they can protect corporate data by preventing (169) through rogue access points. They help control salary costs, by allowing IT staffs to manage larger networks without adding staff. And they can improve overall network mananement by integrating with customers’ existing systems, such as OpenView and UniCenter. Fortunately, it isn’t necessary to measure these benefits to justify investing in WLAN management solutions, which can quickly pay for themselves simply by minimizing time-consuming (170) and administrative chores.

A．chores

B．chains

C．changes

D．links
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