Observation Deck Assignment - Tension in Cables

[b6ttery]

Homework Statement

For my engineering assignment we are working in a group to research, build, test, and write a report on an observation deck.
The little fork in the road we've hit is determining the tension in the cables. There needs to be a moment produced once there is between 20 and 30kg of a uniformly distributed load applied to the beam. We must take into consideration the weight of the beam.
The beam is attached to the middle pylon by a hinge. The deck must fail by the cables snapping/breaking, and nothing else (ie, no breaking of the beam).

We're stuck because we have no clue what sort of formulas/equations we should be using!?
Please help =)

Homework Equations

I know that there's the equations of equilibrium,
Sum of Fx = 0
Sum of Fy = 0
Sum of M = 0
And that,
M=Fd

The Attempt at a Solution

I've had no attempt at solving this equation =(

 

[b6ttery]

Oh, also, we know where the cables are on our deck and hence, the angles they make they the beam. Would anyone like a diagram?

 

[pongo38]

We need a good diagram, and need to know if this is a 2- or 3-dimensional problem.