Two rigid beams of length $\ell$ are hinged together. They make an "A" frame with an angle $\theta = 40^\circ$ due to a piece of cable that keeps the beams from separating beyond that point. The frame is placed on a smooth floor, and supports a 5 kN load, as shown in the figure below. The cable is attached at a distance of $1/2\, \ell$ from where the structure contacts the floor. Assume that the load is large enough that we can completely ignore the mass of the frame.
What is the tension in the cable?