T1-m2 A C bg nB 12 RFr-RFTI-M=Ja a=ra mag-M/ R A +mB +mc/2 F ma(mB g-M,/R) m4+mn+m./2 mol(m+m B l/2)g+M1/R 12 ma +mB+mc/2/ 2 ( / ) A B C A B f T1 m m m m m g M R F + +− =   2 ( 2) A B C B A C f T2 m m m m m m g M R F + + + + = / 2 A B C B f m m m m g M R a + + − = A B C m A mBmC FT1  FT2  RFT2 − RFT1 − Mf = J FT1 = mA a m B g − FT2 = m B a a = R 