正确答案选择A选项0.3对于A木板Tcos37=fA 0.8T=fAfA=uN fA=0.5NN=mg-Tsin37 N=220-0.6T0.8T=0.5N=0.5(220-0.6T)=110-0.3TT=100NfA=80N160N=N对于B木板F=fA+fB200=80+fB =120NfB=u2N2=u2(mBg+N)120=u2(240+160)=400u2u2=0.3