. After the war, a new school building was put up __ bad once been a theatre. A. in which B. where C. where it D. where there 答案:D(2016·无锡卷)一位同学用20s,从一楼走到三楼,他上楼时的功率可能是( )A. 1.5W B. 15W C. 150W D. 1500W
C
【解析】试题分析:先估测人的质量,然后根据G=mg求出重力,再估测一层楼的高度,根据W=Gh求出他上楼时做的功,再由求出功率.一个学生的质量m=50kg,则一个学生的重力:G=mg=50kg×10N/kg=500N,每一层楼的高度为3m,从一楼走到三楼,上升的高度:h=(3-1)×3m=6m,他上楼时克服重力做的功:W=Gh=500N×6m=3000J,则他上楼时的功率:,故ABD错误,...