f1=-r+m(-v+cos0)-()） (N-Mg-mg)dt musin0-(2) f=N一(3) .t很短，N>(Mg+mg)∠ mg [Ndt=musin-(2) Mg -(M+m)v+mucos=u musine mu(cose-usine) V= M+md )1()cos( 0 θ — τ +−+−= uvmMvtf ∫ ( )2(sind) 0 θ — τ =−− mutmgMgN ∫ Q τ 很短， >> + mgMgN )( = μNf — )3( )2(sind ' 0 θ — τ = mutN ∫ − + + umvmM θ = μ um sin cos )( θ mM mu v + − = (cos θ μ θ )sin θ u r gM r gm r N r f r