F = F + F + F2 = (35.4) + (35.4) + (86.6) = 100 1b If needed, the coordinate direction angles of F can be determined from the components of the unit vector acting in the direction of F. Hence, so that u = E = B i + B j + k 35.4 35.4 = - 100 j+ -100 86.6 100 == - 0.354i 0.354j +0.866k = COS -1 (0.354) = 69.3 = cos (-0.354) = 111 = cos (0.866) = 30.0 These results are shown in Fig. 2-30c FIG. 2-30 F= 100 lb x 60 -y 45 , Z F = 100 lb F, F' F = 100 lb F 60 x (b) Z X 30.0 69.3 111