問題詳情
11．一个25kg的小孩从高度为3.0m的滑梯顶端由静止开始滑下，滑到底端时的速度为2.0m／s。取g＝10m／s2，关于力对小孩做的功，以下结果正确的是
(A)合外力做功50J
(B)阻力做功500J
(C)重力做功500J
(D)支持力做功50J
(A)合外力做功50J
(B)阻力做功500J
(C)重力做功500J
(D)支持力做功50J
參考答案
答案：A
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)
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