题干

随着人们生活水平不断提高,私家车已日益普及.如图甲是一种测量小汽车油箱内油量的装置原理图,它主要由电源、压敏电阻R(电阻随所受压力的变化而变化)、油量表(实质上电流表)等组成电路.压敏电阻R在一定范围内的阻值与所受压力的关系如图乙所示,油箱位于压敏电阻上方,电源电压为12V.问:


(1)末放油箱时,电路中的电流是多少?

(2)压敏电阻表面能承受的最大压力是500N,该油量表(电流表)的量程是多少?

(3)若油箱的质量为6.5kg,当油量表(电流表)的示数为0.06A时,则油箱内汽油的重力是多少?(g取10N/kg)

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答案(点此获取答案解析)

解:(1)根据图乙可知,未放油箱时电阻R=400Ω,此时电路中的电流:I1=
U
R
1
=12V

同类题1

阅读理解

    Sitting on the sofa in her family's Michigan home in 2009, looking through the Guinness World Records, 10 year-old Winter Vinecki was surprised to find that the record for the youngest person to complete a marathon on every continent was held by a 27-year-old man. “I can beat that,” she declared. “For Dad. ” And she had every reason to believe she could.

    A natural athlete since the age of 5, Winter had been running together with her mom and uncle, both athletes, and competing in races across the country. Soon, her name was appearing in national competitions. Trophies (奖牌) lined her walls.

    But in 2008, at the age of 9, Winter stopped racing for medals. In May of that year, her father found out he had caught a rare cancer. To raise awareness and funds to fight the disease. Winter started an organization called I earn Winter. Just 10 months after his diagnosis, her father passed away.

    Over the next three years, Winter came first in 20 of the 37 races in which she competed, including four Junior Olympics Cross Country Championships. Along the way, she raised over $ 400,000 to help find a cure for cancer.

    Now 14, Winter is working on her world record to win her cause a place in the Guinness World Records. She recently completed her first marathon in Eugene, Oregon, a race normally limited to runners over 16, finishing in an amazing 3:45:04. “I'm used to racing with adults, and I think it's kind of fun to race past them,” said Winter before the race.

    With six continents to go, Winter has just begun a journey that will take her two years. “Every time I step to a starting line,” Winter says, “I have one thought in mind: keeping my dad's spirit alive.”

同类题2

阅读下面的文言文,完成小题。

郑当时传

    郑当时者,字庄,陈人也。其先郑君尝为项籍将,籍死,已而属汉。高祖令诸故项籍臣名籍,郑君独不奉诏。诏尽拜名籍者为大夫,而逐郑君。

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    郑庄使视决河,自请治行五日。上曰:“吾闻‘郑庄行,千里不赍粮',请治行者何也?”然郑庄在朝,常趋和承意,不敢甚引当否。及晚节,汉征匈奴,招四夷,天下费多,财用益匮。庄任人宾客为大农僦人④,多逋负⑤。司马安为淮阳太守,发其事,庄以此陷罪,赎为庶人。顷之,守长史。上以为老,以庄为汝南太守。数岁,以官卒。卒后家无余赀财。

(《史记》一二○卷)

【注】①洗沐:官员休假算:竹器 ③推毂:推荐 ④僦人:这里指承揽运输的人⑤逋负:拖欠款项