.mg cos eds mvdv .∴s=ld0.∴.gl cos ade0=vddy ".[gl cosai0=[vdv 积分得gl sin0= 三 √2 gl sin0 法向T-ng sin0=ma,=m 带入v可得T=3 ng sin0mg cosds = mvdv ds = ld gl cosd = vdv    = v gl d vdv 0 0 cos    积分得 2 2 1 glsin  = v v = 2glsin  mg  T  v  法向 T − mg  = man sin l v m 2 = 带入v 可得 T = 3mg sin 