本题目来源于试卷: Circular Motion，类别为 美国物理杯赛(Physics Bowl)
[单选题]
07.22: A mass m is pulled outward u 2loxdw jq0zdvjse+ 7t0s2 .fv in;:)antil 1 azwdvvn4+a7 the string of length L to which it is attached makes a 90- degree angle with the vertical. The mass is released from rest and swings through a circular arc. What is the tension in the string when the mass swing4 n1 7vavwz+ads through the bottom ofthe arc?
A. 0
B. $mg$
C. $2mg$
D. $3mg$
E. It cannot be determined.
参考答案: D
本题详细解析:
暂无
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