题目

某同学在做平抛运动实验时得到了如图所示的运动轨迹，a、b、c三点的位置在运动轨迹上已标出．则(1)小球平抛的初速度为________m/s.(g取10 m/s2)(2)小球抛出点的位置坐标为x＝________ cm，y＝________cm. 答案：【答案】 2m/s －10cm －1.25cm【解析】（1）由平抛运动公式，在x轴方向上，在竖直方向上，代入数据解得（2）小球经过b点时竖直分速度，小球从开始运动到经过b时历时，说明小球经过a点时已经运动了ta=0.05 s，所以小球抛出点的坐标为x=－； .Chinese cuisine（菜肴）is widely known and enjoyed in the world. But there is one interesting concept concerning Chinese food which is almost unheard of in the West, and which is becoming increasingly ignored by the youth of the East - the ancient custom of “tonic food.” Tonic food is food which is consumed to improve one’s well-being, or stave off sickness, particularly at times when one is more likely to fall ill. For instance, it was once the custom for new mothers to eat a sesame-oil hot pot every day for the first month after giving birth. It was believed that this dish would benefit the muscles, reduce pain, improve circulation, stimulate sweating, and warm the body.     In fact, some Western theories of health are similar to the beliefs in Chinese tonic food, although each takes a different path toward the very same goal. Western medicine actually recommends some of the exact same ingredients that make up tonic foods. Sesame oil can provide lots of calories, and chicken meat is particularly high in protein. Any Western doctor should be happy to suggest such a Chinese dish after childbirth. The elderly, weak, and young can also benefit greatly from tonic foods, especially during the winter. Some foods, such as goat meat and spinach, are seen as “hot,” while others, such as Chinese cabbage and radish, are seen as “cold.” One should be careful not to eat too much of either “hot” or “cold” food. However, how much “hot” or “cold” food one should eat depends on the time of the year, how the food is prepared and what it is prepared with, and the individual’s health. “Warm” or “cool” tonic foods are strongly recommended. The choices for “warm” and “cool” foods range from simple sea cucumber to the delicacy of bird’s nest soup, depending on the individual’s economic circumstances. The concept of tonic food is far from losing credibility, either with Westerners or practitioners of modern medicine. For example, up until two years ago, tonic foods were added to the meals served at a renowned hospital. What attitude do the young in the East hold towards “tonic food”?（不超过5个词） Why are some Western theories of health considered similar to the Chinese beliefs in tonic food? (不超过11个词) List four factors deciding the amount of tonic food. （不超过20个词） What does the passage mainly talk about? （不超过6个词）