吉川相田是日本岛根县一家旅行社的老板。半年前的一天,他和同行们一起坐大巴车,去大阪参加一个行业会议。在经过松江市郊区时,车上的人突然对着窗外发出了“哇”一声惊呼,吉川相田也下意识地往窗外瞟了一眼,居然看到外面有一座桥的造型很奇特,它的坡度陡得出奇,看上去是一座新造不久、已经通车的水泥桥。这座桥的坡度为什么会这么 Yoshikawa Aida is the owner of a travel agency in Shimane Prefecture, Japan. One day six months ago, he and his colleagues took a bus and went to Osaka to attend an industry conference. After passing the suburbs of Matsue City, the car suddenly issued a “wow” out of the window exclaimed, Yoshikawa Aoyama also subconsciously glanced out the window, actually saw outside the shape of a bridge is very strange, it Steep slope was surprising, it appears to be a newly built soon, has opened to traffic cement bridge. Why is the slope of the bridge so?