题干

在2012年伦敦奥运会上,中国代表团参加了包括田径、体操、柔道等项目的比赛,下列几种比赛项目中的研究对象可视为质点的是(   )

A:在撑杆跳高比赛中研究运动员手中的支撑杆在支撑地面过程中的转动情况

B:帆船比赛中确定帆船在大海中的位置

C:跆拳道比赛中研究运动员的动作

D:跳水比赛中研究运动员在空中的运动情况

上一题 下一题 0.0难度 选择题 更新时间:2017-02-19 03:16:15

答案(点此获取答案解析)

B

同类题3

2014年8月18日,中共中央***、***、中央军委主席、中央财经领导小组组长习近主持召开中央财经领导小组第七次会议,研究实施创新驱动发展战略。***在会议上发表重要讲话强调,创新始终是推动一个国家、一个民族向前发展的重要力量。我国是一个发展中大国,正在大力推进经济发展方式转变和经济结构调整,必须把创新驱动发展战略实施好。
九年级(1)班同学围绕“创新”这一主题开展实践探究活动,请你参与其中并完成相关任务。
第一组同学通过上网搜集到以下信息图片

(1)根据前三幅图片,请揣摩第④幅的内容,写出其名称,并回答这些图片共同说明了什么。(2分)
第二组同学通过查阅资料了解到以下信息
    科技应用
国家
对外技术依存度
科技进步对经济增长贡献率
中国
50%
39%
美国
5%
70%
(2)联系材料,说说我国为什么要实施创新驱动发展战略?(3分)
第三组同学召开主题座谈会交流心得体会
话题一:生活中处处有创新,创新就在我们身边。创新思维是创新实践、创造力发挥的前提。“雨伞”是我们很熟悉的生活用品,它的用途除了遮雨防淋,还有很多,如作为礼物送人、当杂技演员走钢丝的平衡物、当急救用降落伞、广告伞可以做广告宣传、浅色伞可当照相反光板……
(3)请发挥你的创新思维,再说出“雨伞”的两种用途。(2分)话题二:同学们就“培养创新精神”这一主题畅谈自己在日常生活与学习中的做法……
(4)请列出你的发言要点。(3分)

同类题4

      Once I spoke at a high school. After the speech, the principal asked me to see a special student. An     1  had kept the boy home, but he had expressed an interest in meeting me, and it would mean a great deal to him. I agreed.
        He was Matthew.   2 he was born, the doctor told his parents that he would not live to see five, then they were told 3  would not make it to ten. Now he was thirteen. He wanted to meet me because I was a gold-medal weight lifter.
I spent over an hour talking to Matthew. He spoke about   4 and succeeding and seeking(追寻)his dreams.
When we finished talking, I went to my    5 and pulled out the first gold medal I won and put it around his neck. I told him he was more of a winner and knew more about    6   and overcoming obstacles(克服障碍)than I ever would. He looked at it for a while, then took it off and handed it 7 to me. He said, “You are a champion. You earned that medal. Someday when I get to the Olympics and win my own medal, I will show it to you.”
        Last summer I got the news that Matthew had8  and a letter Matthew had written to me a few days before:
Dear Rick,
       My mom said I should send you a thank-you letter. The doctors are   9 to tell me that I don't have long to live any more. But I still smile as much as I can.
        I told you that in the future I was going to the Olympics and win a gold medal. But I know now I'll   10 . I know I'm a champion, and God knows that too. When I get to Heaven, God will give me my medal and when you get there, I will show it to you.
Thank you for loving me.
Your friend
Matthew