小明从滑梯上滑下，速度越来越快，说明______能转化为______能；同时他的臀部有热呼呼的感觉，由此可以判断他的机械能______（选填：“增大”、“不变”或“减小”）．
小明从滑梯上滑下的过程中，位置降低重力势能减小，速度增加动能增大．但由于小明克服摩擦做功，使物体的温度升高，内能增加，部分机械能转化成了内能，所以机械能减小了．
故答案为：重力势，动，减小．
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| Mrs. Yuan is a writer. She is 1 and often helps the poor persons. It was a very cold 2 morning. On the way to her office, she saw an old man 3 on the ground. She came to him and helped him to 4 and bought some water and bread for him. The old man ate up the food quickly and 5 her very much. Then she asked, "Where do you live, Grandpa?" "I have no 6 , madam," said the old man."I have to sleep outside 7 ." "How old are you?" "Ninety-two, madam."Yuan became 8 and went on asking,"Why not live in the old people's house"" 9 I have a son," said the old man."They have 10 admitted (接纳) a person who has children. I have a son." "Where is your son, then?" "He has no children, so the old people's house admitted him." "It's unfair!" said Mrs.Yuan. | ||||
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