Solving Horizontal Beam & Cable System: F, W & T1, T2

[Femme_physics]

Homework Statement

http://img864.imageshack.us/img864/8066/graspcc.jpg

the uniform horizontal beam AC, is held at tip A by a circular joint, and at point B it's held by 2 cables, BD and BE, as described in the drawing. At tip C of the beam acts a vertical force, F:

Given

W = 1 [kN]
F = 4 [kN]

Calculate the forces acting on the cables BE and BD and the reaction force at joint A.

Ignore the cables weight.

The Attempt at a Solution

I get stuck at finding T1 and T2, where the 2 eq 2 unknowns cancel each other out

http://img807.imageshack.us/img807/6979/20031xx.jpg

http://img842.imageshack.us/img842/4901/20032xx.jpg

 

[cupid.callin]

points D,E are in plane of A or something else?
EDIT: ok ... i got it from your solution :)

 

[I like Serena]

Good morning, Fp!

Say, that a sexy problem!

So you have 2 threads keeping that humongous thing up.
But somehow the forces in these 2 threads cancel out?

How about checking your visual cues?

 

[Femme_physics]

Hi ILS

You're right! I confused the signs on sigma Fy. But, I'm still off with the solution manual when it comes to T1 and T2. I equals 8.something [kN] I got

http://img21.imageshack.us/img21/7365/6364k.jpg

But all my A's are correct for the record

 

[I like Serena]

Did you consider all 3 dimensions?

Otherwise it may yet fall!

 

[Yuqing]

Why not consider a geometrical approach? You have the relative proportions for the tensions in the x,y,z directions. Since you've already solved for one of the components, you can scale for the rest accordingly.

 

[Femme_physics]

Did you consider all 3 dimensions?

Otherwise it may yet fall!

Thanks, solved it! And, after that, I solved 5 more 3D statics problem without a hitch! I think I'm getting the hang of it

Why not consider a geometrical approach? You have the relative proportions for the tensions in the x,y,z directions. Since you've already solved for one of the components, you can scale for the rest accordingly.

Yep, always an option thank you.

 

[I like Serena]

Thanks, solved it! And, after that, I solved 5 more 3D statics problem without a hitch! I think I'm getting the hang of it

Good!