本题目来源于试卷: Physics Unit9: Static Equilibrium, Elasticity and Fracture，类别为 通用国际物理
[单选题]
A uniform meter stick is supported by a knjupp oledz- 7v1,+e 6eife edge at the 50-cm mark and has m9 cav9:g+5qwkcyk/g x asses of 0.40 kg and 0.60 kg hanging at the 20-cm and 80-cm marks, respectively. Where (g kv9gax c/5c:9wky+q at what mark) should a third mass of 0.30 kg be hung to keep the stick in balance?
A. $20 \; cm$
B. $25 \; cm$
C. $30 \; cm$
D. $70 \; cm$
参考答案: C
本题详细解析:
暂无
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