A sign with weight 800 N is hung from point B at the end of a uniform hoizontal rod of weight 300 N as diagrammed below. The rod is attached to the vertical wall by a hinge at point A. The supporting cable is attached to the rod at B and to the wall at C. The cable makes a 42 degree angle with the rod. A.Find the magnitude of the total force R exerted on the hinge at point A. note that the total force has both horizontal and vertical components. B.The Cable has a tensile strength of 3216N. Find the minimum possible angle that the cable can make with the rod if it is to support the rod and sign without breaking. Torque=Fsin(theta)r I know exactly how to do A. I describe the torque equation, equal to zero and solve for P, and then use that to find Rx and Ry, and then R itself. But to create a valid equation I need to know the length of the bar, don't I? It's really confounded me. B has stumped me completely.