题目

如图所示，一小球从离粗糙斜面顶端高处以的初速度水平抛出，之后恰好能从斜面顶端沿斜面方向下滑至地面，已知小球在斜面上下滑的时间为2s，斜面长18m。（g取）求： （1） 小球下落h时的竖直速度； （2） 小球落在斜面顶端的速度； （3） 小球下滑到地面的速度。 答案：解：由速度位移公式有vy2=2gh则下落h时的竖直速度为vy=2gh=4m/s 解：小球落在斜面顶端的速度为v=v02+vy2解得v=8m/s 解：设小球下滑到地面的速度为v′，则有x=v+v′2t解得v′=10m/sA boy was born to a couple after they’d been married for eleven years. They were a loving couple and the boy was the apple of their eyes. One morning, when the boy was around two years old, the husband saw a bottle open. He was late for work so he asked the wife to cap the bottle and put it in the cupboard. The mother, busy in the kitchen, totally forgot the matter. The boy saw the bottle and playfully went to it and, interested in its color, drank it all. It happened to be a poisonous medicine meant for adults in small dosages (剂量). When the child fell down, the mother hurried him to the hospital, where he died. The mother was afraid. How would she face her husband? When the heartbroken father came to the hospital and saw the dead child, he looked at his wife and said just four words, “I Love Your Darling”.   The child is dead. He can never be brought back to life. There’s no pointing in finding fault with the mother. Besides, if only he’d taken time to put the bottle away, this wouldn’t have happened. No point in blaming others. She had also lost her only child. What she needed at that moment was comfort from the husband. That is what he gave her.   Sometimes we spend time asking who is responsible or who’s to blame, whether in a relationship, or in a job and miss the warmth in human relationships we could receive by giving each other support.   After all, shouldn’t forgiving someone we love be the easiest thing in the world to do? Treasure what you have. 36. Why didn’t the husband put away the medicine bottle? A. He forgot to do it.                                         B. He had no time to do it. C. He was too lazy to do it.                                  D. He saw his wife do it. 37. In the opinion of the wife, which of the following is responsible for the child’s death?   A. Her husband’s carelessness.                              B. The child’s bad behavior.   C. Her own mistake.                                            D. The producer of the medicine. 38. When the wife heard “I Love You Darling”, she must felt _______.   A. surprised                  B. angry                          C. afraid                          D. indifferent 39. What can be concluded from the passage?   A. Take good care of our children.                         B. Never make serious mistakes.   C. Learn to get along with others.                         D. Learn to forgive others.