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问题 选择题

两个质量不等的小铁块A和B，分别从两个高度相同的光滑斜面和圆弧斜坡的顶点由静止滑向底部，如图2所示，下列说法中正确的是（  ）

A．下滑过程重力所做的功相等

B．它们到达底部时动能相等

C．它们到达底部时速度相等

D．它们分别在最高点时机械能总和跟到达最低点时的机械能总和相等

答案

答案：D

重力做功mgh，由于两物体质量不相同，所以重力做功不同，A错；由动能定理可知重力做功等于动能增量，到达底部的动能不同，B错；由可知两物体到达底部的速度大小相等但方向不同，C错；两物体下滑过程中都只有重力做功，所以机械能守恒，D对；

单项选择题

Want a glance of the future of health care Take a look at the way the various networks of people about patient care are being connected to one another, and how this new connectivity is being exploited to deliver medicine to the patient—no matter where he or she may be.
Online doctors offering advice based on normal symptoms are the most obvious example. Increasingly, however, remote diagnosis will be based on real physiological data from the actual patient. A group from the University of Kentucky has shown that by using personal data assistance plus a mobile phone, it is perfectly practical to send a patient’s important signs over the telephone. With this kind of equipment, the cry asking whether there was a doctor in the house could well be a thing of the past.
Other medical technology groups are working on applying telemedicine to rural (countryside) care. And at least one team wants to use telemedicine as a tool for disaster need—especially after earthquakes. On the whole, the trend is towards providing global access to medical data and experts’ opinions.
But there is one problem. Bandwidth is the limiting factor for sending complex medical pictures around the world—CT photos being one of the biggest bandwidth users. Communication satellites may be able to deal with the short-term needs during disasters such as earthquakes or wars. But medicine is looking towards both the second-generation Internet and third-generation mobile phones for the future of remote medical service.
Doctors have met to discuss computer-based tools for medical diagnosis, training and telemedicine. With the falling price of broadband communications, the new technologies should start a new time when telemedicine and the sharing of medical information, experts’ opinions and diagnosis are common.

The writer chiefly talks about ______.

A. the use of telemedicine
B. the on-lined doctors
C. medical care and treatment
D. communication improvement
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单项选择题

正式通报不包括（）

A.信息不易受到歪曲

B.信息传递准确

C.沟通内容易于保存

D.便于双向沟通
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