题目

如图所示，倾角为37°的斜面与水平面平滑连接。现用力F=14N将一滑块（可视为质点）由静止从水平面上A点拉到B点，在B点时撤去力F，滑块沿斜面向上恰好滑到C点，滑块的质量m=2kg，已知滑块与水平面间的动摩擦因数 ，A、B两点的距离L=2.0m，B点距C点的距离 。假设滑块由水平面经过B点进入斜面时速度大小不变， 已知（sin37°=0.6，cos37°=0.8），（ ）求： （1） 滑块经过B点时的速度大小； （2） 滑块与斜面间的动摩擦因数μ2； （3） When it comes to friends, I desire those who will share my happiness, who has wings of their own and who will fly with me.     When I was in the eighth grade, I had a friend. We were shy and “too serious” about our studies when it was becoming fashionable with our classmates to learn acceptable social behaviors. We said little at school, but she would come to my house and we would sit down with pencils and paper, and one of us would say, “Let’s start with a train whistle（鸣笛）today.” We would sit quietly together and write separate poems or stories that grew out of a train whistle. Then we would read them aloud. At the end of that school year, we, too, were changing into social persons and the stories and poems stopped. When I lived for a time in London, I had a friend. He was in despair（失望）and I was in despair, too. But our friendship was based on the idea in each of us that we would be sorry later if we did not travel over this great city because we had felt bad at the time. We met every Sunday for five weeks and found many excellent things. We walked until our despairs disappeared and then we parted. We gave London to each other. For almost four years I have had a great friend whose imagination brightens mine. We write long letters in which we often discover our strangest selves. Each of us appears, sometimes in a funny way, in the other’s dreams. She and I agree that, at certain times, we seem to be parts of the same mind. It is such comforting companions（陪伴）I wish to keep. One bright hour with their kind is worth more to me than the lifetime services of a psychologist, who will only fill up the healing silence necessary to those darkest moments in which I would rather be with my own best friend. 1.We can infer from Paragraph 2 that the writer ______ finally. A. wasn’t serious about her studies B. didn’t like writing poems or stories C. became popular with her classmates D. developed her proper social behaviors 2.The underlined sentence “We gave London to each other” probably means ______. A. our tour in London was a memorable gift to both of us B. our unpleasant feeling about London disappeared C. we were unwilling to stay away from London D. we waved goodbye to each other in London 3.What is the best title for the passage? A. Unforgettable Experiences. B. Unbelievable Imagination. C. Touching Companions. D. Lifelong Friendship.