题干

高台跳雪运动员从赛道高处滑下,即将到达赛道底部时,运动员双脚使劲一蹬,顺势跃向高空.然后上身前倾,双臂后摆,向前滑翔,两边的雪松飞快地向后掠过.最终,滑雪板稳稳地接触地面.

请你结合上述情境,仿照示例写出高台跳雪运动中所包含的两个物理知识.

示例:运动员从赛道高处滑下﹣﹣重力势能转化为动能.

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答案(点此获取答案解析)

答:高台跳雪运动中,包含的物理知识很多:

①运动员双脚使劲一蹬﹣﹣物体间力的作用是相互的;

②顺势跃向高空﹣﹣利用惯性(动能转化为重力势能);

③上身前倾,双臂后摆﹣﹣减小阻力;

④向前滑翔﹣﹣利用惯性;

⑤雪松飞快地向后掠过﹣﹣以运动员为参照物,雪松向后运动(参照物);

⑥滑雪板稳稳地接触地面﹣﹣力能改变物体的运动状态(滑雪板宽大,对地面压强减小).

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    I was at my parent's dinner table. Before me was a worn journal of thin and discolored pages. It was my grandfather's journal and now belonged to my father. My grandfather had passed away in the months leading up to my birth. I never got to visit the places he had frequently and people who had been a part of his life's journey.

    I was now about to enter his world, through the words he had left behind. Within minutes, I was attracted by the power of the written words. In the magical script before me, I was transported to another age when food was an everyday art, planned, prepared and enjoyed in the company of others, and a time when people had the heart to pause,their own lives to embrace (拥抱)each other's struggles. All this was conveyed to me in the beauty of the words that flowed together to connect with the writer's mind and understand the world they lived in.

    That kind of writing seems to be lost on us today. We have gotten used to writing in bite-sized pieces for a public looking for entertainment, and hungry for information. No wonder, there are nearly 200 million bloggers on the Internet and a new blog is created somewhere in the world every half a second. Instead of adding to our collective wisdom, most of these writings reflect the superficiality (肤浅)and impatience of our day and age.

    This not only robs us of the skill of writing impressive essays, it also prevents us from exploring what is truly important. Writing humbles us in a way that is vital for our character growth, by reminding us about the limits of the self and our appropriate place in the vast flow of life. Writing frees us by helping us explore the unknown so that we truly open up to the magic of the world around us. I saw all of this in the writing s of my grandfather. And I've seen it again and again in the writings of the greatest thinkers of humanity. Their writings reflect deep thought on issues of human importance.