题目

如图所示，一固定容器的内壁是半径为 R的半球面；在半球面水平直径的一端有一质量为 m的质点 P，它与容器内壁间的动摩擦因数为 µ，由静止释放的质点 P下滑到最低点时，向心加速度的大小为 a．重力加速度大小为 g．则此时（ ） A． 质点 P处于失重状态 B． 容器对质点 P的支持力大小为 ma+mg C． 质点 P受到的摩擦力大小为 µmg D． 质点 P的速度大小为29、An old man was sitting in front of his house. Just then, a young man walked up to him, “Excuse me, what kinds of people live in this town?” asked the young man. “What kinds of people lived in the town you left?” the old man replied with a smile. “Oh, they were unkind and angry. I couldn’t wait to leave” said the young man. “Then those are exactly the same kinds of people you will find in this town. You might not be happy here. ” After hearing his words, the young man moved on. About an hour later, another young man walked to the old man with a big smile on his face. “Good afternoon, sir. Could you tell me what kinds of people live in this town?” the young man asked. “What kinds of people lived in the last town you lived in?” the old man asked. “Oh, they were amazing! They were polite and helpful. I really didn’t want to leave.” answered the young man. “You’ll find the same kinds of people in this town… Welcome! I hope you decide to stay here. ” 根据短文内容，判断句子正（T）、误（F）。 1. The old man was playing chess when a young man walked to him. 2. The first young man wanted to ask him the way to the nearest town. 3. The second young man was from a town where people were very polite and helpful. 4. The first young man decided to stay after hearing the old man’s answer. 5. The old man hoped the second young man would live in his town.