A、F1(1)、F1=G总/3=(50N+150N)/3=66.7NF2=G总/2=(50N+200N)/2=125N所以F1(2)、η1=(Gh)/(FS)=(Gh)/(Fx 3h)=G/(3F)=150/(3x66.7)=75%η1=(Gh)/(FS)=(Gh)/(Fx 2h)=G/(2F)=200/(2x125)=80%