3) 瞎猫死鼠解.

来源: 于 2011-09-18 08:16:45 [旧帖] [给我悄悄话] 本文已被阅读：次

Stone is mg on the face and 0 in the center. So,in side,the near center the lighter,linearised,F(x)=x/R*mg,...We get the same answer.