F Rx =360.c0s60°+550+380c0s30+300.c0s70 =1161.7N) =360.sin60°+0380.sin30°-300.sin70° =-160.13(N) F=V(E)P+(Rv尸=117268N 01=609 合力与x轴的夹角 F 03-30° tana 2,=-7°50 a4=70°F 合力与x轴的夹角