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问题 计算题

一物体做匀加速直线运动，途中由A经B到C历时4s，前2s从A到B和后2s从B到C的位移分别为24m和32m。求：

（1）物体运动的加速度为多少？

（2）物体在A点和C点的瞬时速度的分别为多少？

答案

（1）a=2m/s2  （2）vA=10m/s，vC=18m/s

名词解释

迭加偏移
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单项选择题

How should one invest a sum of money in these days of inflation (通货膨胀) Left in a bank it will hardly keep its value, however high the interest rate is. Only a brave man, or a very rich one, dares to buy and sell on the Stock Market. Today it seems that one of the best ways to protect your savings, and even increase your wealth is to buy beautiful objects from the past. Here I am going to offer some advice on collecting antique clocks, which I personally consider are among the most interesting of antiques.
I sometimes wonder what a being from another planet might report back about our way of life. "The planet Earth is ruled by a mysterious creature that sits or stands in a room and makes a strange ticking sound. It has a face with twelve black marks and two hands. Men can do nothing without its permission, and it fastens its young round people’s wrists so that everywhere men go they are still under its control. This creature is the real master of Earth and men are its slaves."
Whether or not we are slaves of time today depends on our culture and personality, but it is believed that many years ago kings kept special slaves to tell the time. Certain men were very clever at measuring the time of day according to the beating of their own hearts. They were made to stand in a fixed place and every hour or so would shout the time. So it seems that the first clocks were human beings.
However, men quickly found more convenient and reliable ways of telling the time. They learned to use the shadows cast by the sun. They marked the hours on candles, used sand in hourglasses, and invented water-clocks. Indeed, any serious student of antiques should spend as much time as possible visiting palaces, stately homes and museums to see some of the finest examples of clocks from the past.
Antique clocks could be very expensive, but one of the joys of collecting clocks is that it is still possible to find quite cheap ones for your own home. After all, if you are going to be ruled by the time, why not invest in air antique clock and perhaps make a future profit

The purpose of the passage is ______.

A．to introduce the culture of antique clocks

B．to offer some advice on collecting antique clocks

C．to compare different ways to make a future profit

D．to tell people that we are the slaves of clocks
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