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2006年全国普通高等学校招生理科综合测试(全国卷Ⅰ)的第20题的答案,部分师生之间存在着很大的争议.为了讨论问题方便现摘录原题如下:原题一位质量为 m 的运动员从下蹲状态向上起跳,经Δt 时间,身体伸直并刚好离开地面,速度为v.在此过程中()A.地面对他的冲量为 my+mgΔt,地面对他做的功为1/2mv~2B.地面对他的冲量为 mv+mgΔt,地面对他做的功为零C.地面对他的冲量为 mv,地面对他做的功为1/2mv~2D.地面对他的冲量为 my-mgΔt,地面对他做的功为零该题的参考答案是选项 B,分析过程如下:
In 2006 the National College Entrance Examination Science Comprehensive Test (Volume I) the 20th answer, some teachers and students there is a lot of controversy. In order to discuss the problem is excerpts excerpts are as follows: m athletes jump up from the squatting state, by Δt time, the body straight and just leave the ground, the speed v. In the process () A. The impulse on the ground for him my + mgΔt, the ground to him to do The work is 1 / 2mv ~ 2B. The impulse on the ground for him is mv + mgΔt, the ground work done to him is zero C. The impulse on the ground for him is mv, the work done by the ground to him is 1 / 2mv ~ 2D. The impulse on the ground for him is my-mgΔt, and the ground does zero for him. The reference answer to this question is option B, and the analysis process is as follows: