某战士在倾角为30°的山坡上进行投掷手榴弹训练．他从A点以某一初速度 $v_0=15\sqrt{3}$ m/s沿水平方向投出手榴弹后落在B点．该型号手榴弹从拉动弹弦到爆炸需要5s的时间，空气阻力不计，（g=10m/s²）求：

    Mrs. Yuan is a writer. She's 1 and often helps the poor person. It was very cold one snowy morning. On the way to her office, she saw an old man 2 on the ground. She came to him and help him to 3 and bought some porridge and bread for him. The old man ate up the food quickly and  4 her very much. Then she asked. “Where do you live, Grandpa?”

     “I have no  5  madam,” said the old man. “ I have to sleep outside 6.”

     “How old are you?” “Ninety-two.” Mrs Yuan became 7 and went on asking, “Why not live in the old people's house?”  8 I have a son,” said the old man. “they've 9 admitted(接纳) a person who has children.”

     “Do you have any children?”

     “Yes,” answered the old man. “I have a son.”

     “Where is your son, then?”

     “He has no children, 10 the old people's house admitted him.”

     “It's unfair!” said Mrs. Yuan. She overcame several difficulties and at last helped him to live in the old people's house.

5年考古发掘，南昌西汉海昏侯大墓中清理出土了文物1万余件。成套出土的编钟、编磬、琴、瑟、排箫、伎乐俑；数以千计的竹简、木牍以及有文字的漆笥、耳杯；10余吨近200万枚五铢钱；惟妙惟肖的青铜雁鱼灯、青铜火锅；镶嵌着玛瑙、绿松石和宝石的青铜镜，大量马蹄金、金饼等等，都是汉代考古文物珍品，不少是首次发现。

西汉大墓及海昏侯国遗址紫金城等是我国目前发现的面积最大、保存最好、内涵最丰富的汉代侯国聚落遗址，是重要的国家级历史文化遗产，具有重大研究和展示利用价值。