2014年泛珠三角及中华名校物理奥林匹克邀请赛试题及答案.pdfVIP

2014 年泛珠三角及中华名校物理奥林匹克邀请赛 Pan Pearl River Delta Physics Olympiad 2014 Pan Pearl River Delta Physics Olympiad 2014 2014 年泛珠三角及中华名校物理奥林匹克邀请赛 Sponsored by Institute for Advanced Study, HKUST 香港科技大学高等研究院赞助 Part-1 (Total 6 Problems) 卷-1 （共6 题） (9:00 am – 12:00 pm, 6 February, 2014) 1. Sunset Twice a Day (6 points) 一天两观日落 （6 分） Presently the tallest tower in the world is Burj Khalifa in Dubai. Its height is 828 m. An Internet news article reported that one can watch sunset twice in one day with this tower. 杜拜的哈利法塔是现时世界上最高的建筑，高度为 828 米。互联网上有新闻文章报导，可以利用 这塔在一天内两次观看到日落。 (a) What is the time range of sunset between the bottom and the top of the tower? Give your answer in minutes. Parameters: Earth’s radius = 6400 km. Distance between Sun and Earth = 1.5  1011 m. (3 points) 试求塔底和塔顶之间日落时间的范围。答案请以分钟为单位。参数：地球半径 = 6400 公里。 太阳和地球之间的距离 = 1.5  1011 米。 （3 分） (b) Burj Khalifa also has the world’s third fastest elevator (lift) with a speed of v = 10 m/s. Immediately before the elevator starts moving upwards at the speed v from the bottom of the tower, a tourist in the elevator views the sunset. When he reaches the observatory at the height of 452 m, he found that the Sun has risen. Calculate the inclination angle of the Sun above the horizon. Give your answer in degrees. (3 points) 哈里发塔还拥有世界第三快的电梯，速度可达v = 10 m/s 。有电梯内的游客，在电梯从塔底开 始上升前一瞬看到日落，其后电梯以速度 v 上升。当他到达在 452 米高度的观景台时，发现 太阳上升了。试计算太阳在地平线以上的仰角。答案请以度为单位。 （3 分） 2. Radiocarbon Dating (5 points) 放射性碳年龄测定法 （5 分） Radiocarbon dating is a technique used in archeology to estimate the age of organic materials, such as wood and leather. It uses the fact that the density of 14C a