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 holds a 20 kilrh 0kqx 7,1j2;b frm-z9h uzr.zurf3qogram 1vbe;qf4*9y jhc )rdf sheet of wallboard 3 meter above the floor for 4 seconds. During these 4 secondsho ;yce *9q4ff)br1vdh jw 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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