See the figure. a) Find the resultant force b) Find the angle between the forces F_1 and F_3. Solution The forces will be distributed in compenents F1 are divided into two components F1y=F1sin60, F1z=F1cos60. F3 F3y=F3cos60,F3z=F3sin60 Resultant F net y= F1 sin60+F3cos60 Resulltant F net z F3cos60+F1sin60 a Angle between two vectors Cosa=(Fnety.Fnetz)/Sqrt||Fnety||.||Fnetz|| =(F1sin60+F3cos60)2/(F1sin602+F3cos602)=U.V say Then evaluating and will get angle Cos-1(U.V)=Angle between the two forces..