流量表示单位时间内通过某一横截面的流体体积，用字母Q表示。流量监测是抗洪防汛中的一项重要工作。
（1）如图甲所示，水流在粗细均匀的水平管道内向右匀速流动，设水流速度为v，管内通道的横截面积为S．取一段管道AB，水从B端流到A端所用时间为t，则AB间水柱的长度l= ，体积V= （要求用S、、t表示）．根据流量的定义Q=V／t可得Q=vS，表示流量等于流速与横截面积的乘积．
（2）打开水龙头，自来水通过导管流过如图乙所示的玻璃管．待水流稳定后，比较图中1、2两处的流速， （选填“1”或“2”）处的流速较大；比较C、D玻璃管中的水面高度， （选填“C”或“D”）管中的水面较高。
（3）打开水龙头后，只要水流不散开，就可以观察到水柱越来越细，如图丙所示．产生这种现象的原因是：水往下流时，重力势能转化为 能，运动速度变 ，而流量不变，根据Q=vS可知，水柱的横截面积减小，因此水柱越来越细．
（1）vt vSt
（2）2 C
（3）动 大
An elderly carpenter(木匠) was ready to retire. He told his boss his plans to 1 the business and live a more relaxed life with his wife. He would miss the pay, but he needed to retire. The boss was 2 to see his good worker go, and asked if he could build just one more house as a personal favor. The carpenter said yes, 3 it was easy to see that his heart was not in his work. He used poor skills and 4 materials. It was an unfortunate way to 5 his career. When the carpenter finished his work, the boss came to 6 the house. After he checked it out, he handed a 7 to the carpenter. “This is your house,” he said. ‘It is my gift to you.” What a shame！If he knew he was building his own house, the old man would have done it all so 8 . So it is with all of us. Think of your life as a 9 . Each day you hammer a nail(钉子), place a board, or set up a wall. You must try your best to build the house wisely because it is the only life you will ever have. Your life tomorrow will 10 from the attitudes you choose today. 小题1:.
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