help please Write force F in Cartesian vector form What is the moment of the force F about point A Identify zero force members Solution 1) A=(0.3.2) and B=(6,0,4) so AB=(6,-3,2) so unit vector along AB=(6,-3,2)/(magnitude) magnitude=sqrt(36+9+4)=7 so F=70*(6i-3j+2k)/7=60i-30j+20K 2) B=(2,5,6) A=(1,-1,1) so AB=(1,6,5)=r torque=r*F=(i+6j+5k)*(30i+40j-5K) =-100i-100j-140K 3) DF, BH should be zero force member since truss member cannot sustain tangential load note .