: mAg-TA =mAdA B:Tn-f-mndn N-mng =0 TA=TB 附加方程 f=uN ◆ aA=aB= (mA-umB) (mA+mB)）附加方程 Nf aa TT = μ = = BA BA g mm mm aa )( ( ) BA A B BA + − == μ Α: Β: AAAA − = amTgm B BB − = amfT 0 − BgmN =