出管路中总的压头损失的计算式，并说明减低流体阻力的途径。_爱下问搜题

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问题问答题简答题

出管路中总的压头损失的计算式，并说明减低流体阻力的途径。

答案

参考答案：

管路中总的压头损失为：ｈ损＝入[（L+ΣL当）/d]×（U2/2g）.减低流体阻力的途径：A.管路尽可能短一些，尽量走直线，少拐弯。B.没必要的管件和阀尽量不装。C.适当放大管径。

完形填空

My father was raised in a fatherless home at a time when the family of five struggled to survive, which caused my father to be extremely tightfisted(吝啬) with money.
When we children became    16  that other children got pocket money from their parents, we made a(n)   17  to ask our father from some. Immediately his face turned stone-cold, and he said, “If you’re old enough to ask, you’re old enough to    18 .” And we had to seek odd jobs about the neighborhood.
He didn’t    19  his attitude as we grew into adulthood. There was a time when    20  of us had a car, so we had to ride a    21  whenever we came home. Though the bus stopped about two miles from home, Dad never met us, 22  in bad weather. If someone    23  (and my brothers did a lot), he’d say in his    24  father-voice. “That’s what your legs are    25 !”
One spring morning I was on the bus home from    26 . Tests and long hours in labs had    27  me exhausted. As other students were    28  at their stops. I looked silently out of the window. Finally, the bus came to a    29  at my destination, and I    30 , carrying my suitcase to begin the long journey home.
The row of privet hedge(树篱) came into    31 , which lined the driveway that climbed the hill to our house. I stopped to put a book in the suitcase. When I stood up, I saw something gray    32  along the top of the hedge toward the house.
It was the top of my father’s head. I    33  then, each time I came home, he would stand behind the hedge, watching,    34  he knew I had arrived safely. I held back my tears. He did care,   35 .
Upon reaching home, I found my father innocently in his chair. “So! It’s you!” he said, his face lengthening into surprise.

A．stepped off

问答题

需要是有机体活动积极性的源泉。