题干

如图,A、B两个正方体,它们的边长之比为2:1,密度之比为4:3,先将B放在水平桌面上,再将A叠放在B的正上方,则A对B的压力与B对桌面的压力之比F1:F2为____,A对B的压强与B对桌面的压强之比P1:P2为____

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32:35,32:35

同类题4

课外阅读拓展

    夜深了,一位巴格达商人走在黑漆漆的山路上。突然,有个神(秘 密)的声音传来:“弯下腰,请多捡些小石子,明天会有用的!”商人决定执行这一指令,便弯腰捡起几(棵 颗)石子。到了第二天,当商人从袋中掏出“石子”看时,才发现那所谓的“石子”原来是一块块亮晶晶的宝石!自然,也正是这些宝石,使他立(既 即)变得后悔不迭:天!昨晚怎么就没有多捡些呢?

    这是科学家巴甫洛夫讲的一个故事。尤其发人深省的是,他在讲完故事后说:“教育就是这么回事——当我们长大成人之后,才会发现以前学的科学知识是珍贵的宝石,但同时,我们也会觉得可惜,因为我们学的毕竟太少了!”

    不是吗?教育送给别人的明明是瑰丽的“宝石”,可总有人因为弯腰太累视而不见,结果白白地错过了许多机会。

    还有个故事更意味深(常 长),是歌德在他的叙事歌谣里讲的。耶稣带着他的门徒彼得远行,途中发现一块破烂的马蹄铁,耶稣就让彼得把它捡起来。不料彼得懒得弯腰假装没听见,耶稣没说什么就自己弯腰捡起马蹄铁,用它从铁匠那儿换来三文钱,用这钱买了十八颗樱桃。出了城,二人继续前进,经过的全是茫茫的荒野。耶稣猜到彼得渴得够呛,就让藏于袖中的樱桃悄悄地掉出一颗,彼得一见,赶紧捡起来吃。耶稣边走边丢,彼得也就狼狈地弯了十八次腰。于是琊稣笑着对他说:“要是你刚才弯一次腰,就不会在后来没完没了地弯腰。小事不干,将来就会在更小的事情上操劳。”

    不去弯腰或疏于弯腰,是糊涂;而耻于弯腰者,肯定是傻子!

同类题5

    Once I thought love meant flowers, gifts and sweet kisses. So, I really doubted whether there was any love between my parents. Every day they were working hard to pay for my high school. They didn't act in the romantic ways that I read in books and saw on TV, and they certainly didn't send flowers to each other on Valentine's Day (情人节).
    One day, my mother was sewing a quilt (被子). I asked her if there was any love between her and my dad. She stopped and raised her head in surprise. Then she went on with her work without saying anything. I was very worried because I thought I had hurt her feelings. But after a few minutes she said, “Look at this thread (线). Sometimes it appears, but most of the time it disappears in the quilt. If life is a quilt, then love is the thread. It can hardly be seen anywhere or at any time, but it's really there, and makes the quilt long-lasting.” I listened carefully but I didn't understand her until the next spring.
    My mother suddenly got seriously ill and had to stay in hospital for about a month. Every morning and evening after she returned from the hospital, my father helped her walk slowly along our country road. There were many beautiful flowers, green grass and trees, and the sun gently shone through the leaves. All of this made the most beautiful picture in the world. Reading their eyes, I knew they love each other deeply. From this experience, I realized that love is just a thread in the quilt of our lives. Love is inside, making life strong and warm.