本题目来源于试卷: 2011 美国F=ma物理竞赛 F=ma physics competition，类别为 美国物理杯赛(Physics Bowl)
[单选题]
Jonathan applies a normal force that mfzghyfm je) ;m+ d sl/+(o.:wis just enough to keep ys.jrz306owb) xiz n.the rope from slipping. Becky makes a small jump, barely leaving contact with the floor of the box. Upon landing on the box, the force of the impact causes the ropj biz0ynosr 6zw..3x )e to start slipping from Jonathans hand. At what speed does the box smash into the ground? Assume Jonathans normal force does not change.
A. $\sqrt{2 g H}\left(\mu_{k} / \mu_{s}\right)$
B. $\sqrt{2 g H}\left(1-\mu_{k} / \mu_{s}\right)$
C. $\sqrt{2 g H} \sqrt{\mu_{k} / \mu_{s}}$
D. $\sqrt{2 g H} \sqrt{1-\left(\mu_{k} / \mu_{s}\right)}$
E. $\sqrt{2 g H}\left(\mu_{s}-\mu_{k}\right)$
参考答案: A
本题详细解析:
暂无
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