赵军同学在家里想知道某种食用油的密度,于是他利用学过的物理知识设计了一种求食用油

题型:问答题

问题:

赵军同学在家里想知道某种食用油的密度,于是他利用学过的物理知识设计了一种求食用油密度的方法.他找来一支直径均匀、一端封闭的玻璃管,往玻璃管里放人适量的铁砂,管口朝上放入水里,玻璃管竖直浮在水中,静止后测出玻璃管露出水面的长度为总长度的

2
5
;再把玻璃管放入待测的食用油里,玻璃管竖直浮在油中,静止后测出玻璃管露出油面的长度为总长度的
1
4
.通过计算他知道了这种食用油的密度.问这种食用油的密度是多少?

考点:物体的浮沉条件及其应用密度的计算
题型:问答题
“直线(m-2)x+(m+2)y-3=0与直线(m+2)x+3my+1=0相互垂直”是“m=
1
2
”的什么条件(  )
A.充分必要B.充分而不必要
C.必要而不充分D.既不充分也不必要
题型:问答题

防治血友病出血最重要的措施是()

A.压迫止血

B.抗感染治疗

C.脾切除术

D.用免疫抑制剂

E.补充缺失的凝血因子

题型:问答题

急性苯的氨基化合物中毒的特效解毒药()

A.硫酸钠

B.普鲁士蓝

C.亚甲蓝

D.亚硝酸钠

E.硫代硫酸钠

题型:问答题

发动机在冷态情况下发动,需要供给()的混合气,故要把化油器阻风门(),以()空气的进入量。

题型:问答题

It’s a typical Snoopy card: cheerful message, bright colors, though a little yellow and faded now. Though I’ve received fancier, more expensive cards over the years, this is the only one I’ve saved. One summer, it spoke volumes to me.
I received it during the first June I faced as a widow to raise two teenage daughters alone. In all the emotional confusion of this sudden single parent- hood, I was overwhelmed with, of all things, the simplest housework: leaky taps, oil’ changes, even barbecues (烧烤). Those had always been my husband’s jobs. I was embarrassed every time I hit my thumb with a hammer or couldn’t get the lawnmower (割草机) started. My uncertain at- tempts only fueled the fear inside me: How could I be both a father and mother to my girls Clearly, I lacked the tools and skills.
On this particular morning, my girls pushed me into the living room to see something. (I prayed it wasn’t another repair job). The "something" turned out to be an envelope and several wrapped bundles on the carpet. My puzzlement must have been plain as I gazed from the colorful packages to my daughters’ bright faces.
"Go ahead! Open them!" they urged. As I unwrapped the packages, I discovered a small barbecue grill (烧烤架) and all the necessary objects in- eluding a green kitchen glove with a frog pattern on it.
"But why" I asked.
"Happy Father’s Day!" they shouted together.
"Moms don’t get presents on Father’s Day," I protested.
"You forgot to open the card," Jane reminded. I pulled it from the envelope. There sat Snoopy, on top of his dog house, merrily wishing me a Happy Father’s Day. "Because," the girls said, "you’ve been a father and mother to us. Why shouldn’t you be remembered on Father’s Day"
As I fought back tears, I realized they were right. I wanted to be a "professional" dad, who had the latest tools and knew all the tricks of the trade. The girls only wanted a parent they could count on to be there, day after day, performing repeatedly the maintenance tasks of basic care and love.
The girls are grown now, and they still send me Father’s Day cards, but none of those cards means as much to me as that first one. Its simple message told me being a great parent didn’t require any special tools at all--just a willing worker.

Which of the following statements is true about the first Father’s Day card

A. It made the mother eager to get the latest tools.
B. It praised the mother as a professional dad.
C. Its fancy design impressed the mother most.
D. It showed the girls’ appreciation for their mother’s love.

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