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把一个小球以30m/s的速度水平抛出,它落地时的速度为50m/s.(g取10m/s2)求:

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同类题1

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    凡是到都江堰参观的人都要来看看索桥。那天我从山上二王庙下来,在索桥上来回走了两次。桥身微微摆动,我往前走,桥也好象在往前走。一个乡下人挑着担子迎面走来,桥一下子动的厉害了。我走过他身边,加快脚步往高处去。忽然起了一阵笑声,两个小孩子从高处跑下来,桥接着大大动了一会儿。我连忙走上高处,又继续往下走。

    我刚走到一半路程,就停下来,站在栏杆前埋头看下面。我的眼光正落在“分水鱼嘴”上。我起初看不出来这个光滑的、鱼嘴般的“石头”是什么东西,后来才知道它是把岷江分为内外两条江的工程。这个“鱼嘴”在都江堰的前端,都江堰便是两千两百年以前李冰父子在岷江中修筑的一条大堤。二王庙就是为了纪念李冰和他的儿子二郎修建的。

我看看“鱼嘴”,看看“鱼嘴”两旁数不清的砂石,我又往前走了。回来的时候,我把“鱼嘴”再看了一阵。“鱼嘴”依旧摆在那里,看一百遍也看不出什么变化,可是在它上面,我好象看到了两千两百多年前的人们的手和心。这个石头是会说话的。那许多用手建造了这个“鱼嘴”的人,虽然没有留下名字,可是留下了他们的心。就在离这里九公里的紫坪铺,在将近一公里长的河谷的两岸,上千忙碌工作的年轻人,他们的心不是跟两千两百多年前那些人的心一样么?大的水电站就要在那里动工修建了。

同类题5

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    It started as a special day for Wesley Autrey, a 50-year-old construction worker in New York City. It was about 12:45 P.M., and he was waiting on a subway platform (月台) to take his daughters home before he went to work. He suddenly noticed a man nearby have convulsions (抽搐) and fall down suddenly. Mr. Autrey and two women went to help the stranger. The man, Cameron Hollopeter, managed to get to his feet, but then stumbled (绊倒) at the edge of the platform and fell onto the subway tracks. Mr. Autrey looked up and saw the lights of the subway train coming near through the tunnel.

    Mr. Autrey jumped onto the track immediately. He realized that he didn't have time to get Mr. Hollopeter and himself back up on the platform before the train arrived, so he lay on top of the man and pressed down as hard as he could. Although the driver tried to stop the train before it reached them, he couldn't. Five cars passed over them before the train finally stopped. The cars had passed only inches from his head.

    New York loves a hero. Mr. Autrey became an overnight hero and was named the “Subway Superman”. New York City Mayor Michael Bloomberg gave him the Bronze Medallion, the city's highest honor. He was asked to appear on several TV talk shows. He was also rewarded with money and gifts, such as $10,000 from Donald Trump, a $5,000 gift card from the Gap clothing store, a new Jeep, and Beyonce concert tickets.

    How did Autrey react (反应) to all this? He said, “I don't feel like I did anything great; I just saw someone who needed help. I did what I felt was right”.