本题目来源于试卷: Overweight and underweight，类别为 美国物理杯赛(Physics Bowl)
[单选题]
07.13: Astudent weighing 500 N stands on nha)i +0/vtuq a bathroom scale in the school’s elesce;je.2a+ho vator. When the j;ec.o2sa + ehscale reads 520 N, the elevator must be
A. accelerating upward.
B. accelerating downward.
C. moving upward at a constant speed.
D. moving downward at a constant speed.
E. at rest.
参考答案: A
本题详细解析:
暂无
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