2011年8月我国自主研制的深海探测器--“蛟龙号”(如图1所示)在太_爱下问搜题

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问题计算题

2011年8月我国自主研制的深海探测器--“蛟龙号”(如图1所示)在太平洋海域成功完成5000m深海探测。2012年6月它将再赴马里亚纳海沟挑战7000m深海探测(不考虑海水密度变化，密度ρ取1.0×10³kg／m³，g取10N／kg)。

(1)若“蛟龙号”能承受的最大压强是7.2×10⁷Pa，则它能下潜的最大深度是多少?(不考虑大气压)

(2)“蛟龙号”上一面积为50cm²的观测窗口：在上述两种深度的探测中承受的压力增加了多少?

(3)“蛟龙号”完成任务后．漂浮在海面上，由起重装置将其匀速竖直吊离水面，起重装置起吊拉力的功率随时间变化的图象如图2所示，图中P₂＝2P₁。起吊过程中“蛟龙号”总质量为22吨，求t₁时刻“蛟龙号”的排水体积(不考虑水的阻力)。

图1 图2

答案

解；

(1)由液体压强公式p＝ρgh代入数据解得：h＝7200m

(2)由△F＝ρg△hs代入数据解得：△F＝1×10⁵N．

(3)设在t₁、t₂时刻起重装置对探测器的拉力分别为F₁、F₂，探测器的速度为v，t₁时刻探测器的排水体积为V_t1、t₂时刻探测器受力平衡，有：F+ρgV＝mg

F₂＝mg由已知可得：F₂v=2F₁v由以上三式代入数据可浮，V＝11m³。

完形填空

阅读下面短文，掌握其大意，从每题所给的A、B、C、D四个选项中，选出最佳选项。
James’s New Bicycle
James shook his money box again. Nothing! He carefully __36__ the coins that lay on the bed. $24.52 was all that he had. The bicycle he wanted was at least $90! __37__ on earth was he going to get the __38__ of the money?
He knew that his friends all had bicycles. It was __39__ to hang around with people when you were the only one without wheels. He thought about what he could do. There was no __40__ asking his parents, for he knew they had no money to __41__.
There was only one way to get money, and that was to __42__ it. He would have to find a job. __43__ who would hire him and what could he do? He decided to ask Mr. Clay for advice, who usually had __44__ on most things.
“Well, you can start right here,”said Mr. Clay. “My windows need cleaning and my car needs washing.”
That was the __45__ of James’s odd-job(零工) business. For three months he worked every day after finishing his homework. He was amazed by the __46__ of jobs that people found for him to do. He took dogs and babies for walks, cleared out cupboards, and mended books. He lost count of the __47__ of cars he washed and windows he cleaned, but the __48__ increased and he knew that he would soon have __49__ for the bicycle he longed for.
The day __50__ came when James counted his money and found $94.32. He __51__ no time and went down to the shop to pick up the bicycle he wanted. He rode __52__ home, looking forward to showing his new bicycle to his friends. It had been hard __53__ for the money, but James knew that he valued his bicycle far more __54__ he had bought it with his own money. He had __55__what he thought was impossible, and that was worth even more than the bicycle.

B．introduction

C．requirement

C．suitability

单项选择题

导绳器外圈有（）时，外圈应报废。

A、裂纹

B、磨损

C、变形