Resolve all the Tension into horizontal and vertical forces

[masterofthewave124]

One end of a chord is attached to the ceiling at D and another to the wall at A. Masses of W kg and 20 kg are attached to the cord so that it assumes the shape shown on the right. Find W and the tension in each of AB, BC, and CD.

http://img126.imageshack.us/img126/9884/forces4zx.jpg

stuck on this question...probably due to the lack of information. these are my thoughts so far: do i want to isolate small areas and solve for the values related to them? for example, taking the point B, tensions BC, AB and the 20 kg are attached to this, do i want to start here? using the values solved, can i proceed to points C and D?

 

[mezarashi]

A good strategy would be to start writing down equations and gradually solving for the unknowns. You'll need information from analysis of several key points. We can start from point B, where you can write an equation in the y-direction. The segment BC sin30 needs to be able to support 20kg. Try a similar analysis at point C. Lastly, try analyzing the entire system. The segment from D sin60 must support W+20kg.

Add up these equations (i.e. solve them simultaneously).

 

[Delzac]

The main thing is to resolve all the Tension into horizontal and vertical forces. And note that the system is in equilibrium.(No net force in vertical and horizontal direction)

 

[Delzac]

By the way what is the ans for W ? i try to do it for the fun of it. :P