本题目来源于试卷: Work Energy and Power，类别为 美国物理杯赛(Physics Bowl)
[单选题]
99.14: A construction laborer vln2s w8 fooqbhopjb 34+/tv,m 5h/-n holds a 20svc k-()vd 5g,o7k3ildm+ xp t kilogram sheet of wallboard 3 meter above the floor for 4 seconds. sd x(5d+ik)v3 kpo7gl-vtc ,m During these 4 secondshow much power was expended on the wallboard?
A. 2400 watts
B. 320 watts
C. 27 watts
D. 15 watts
E. none of these
参考答案: E
本题详细解析:
暂无
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