Static Equilibrium question...?

The question reads:





A roof truss is made of two rafters, and a tie beam. Each end of the tie beam is supported by a wooden post. If a 100kg mass is suspended from the rafters, as shown, determine:





a.) The compression in each post


b.) The compression in each rafter


c.) The tension in each tie beam





So the diagram is an isoceles triangle sitting on two posts. The length of the base of the triangle is 12.0m, and the 100kg mass is hung from the top of the triangle.





I got the force of gravity on the mass (981N [Down]), and the length of each rafter (6.5m) and their angle to the 12.0m base (25* each).





But I don't know what to do from there.

Static Equilibrium question...?
Good start


Next write force equilibrium equations


The sum of x forces=0


The sum of y forces=0





(Note: place the weight on the y-axis where x=0.)





Also, just in case, don't forget that the sum of moments about any point is also 0.








The sum of x forces=0


Force components along the rafters


F1 cos(25) + F2cos(25) + F3=0





F3=tension on the beam


F1=F2= compression on each rafter.








The sum of y forces=0





W - F1 sin(25) - F2sin(25) =0


F1=F2 and F1 sin(25)=Fp (post compression)