Circular Motion - Triangular Frame

[Ruler of Hell]

Homework Statement

The Attempt at a Solution

I'm going to post all that I figured out or tried. Most of it is really just pieces of information that I don't know how to put together.

The frame is accelerating, so I have to apply a pseudo-force of $$\frac{3mg}{2}$$ on B and C in the leftward direction.
The Center of Mass of the system lies on the midpoint on B and C. I know the distance between the CoM and A.

I tried energy conservation, taking zero potential at BC. That didn't help either.

 

[cupid.callin]

i can't see your question
is it a pic?

 

[Ruler of Hell]

Yup. Here's the link:
http://i.imgur.com/2ykKR.jpg

 

[cupid.callin]

If i am guessing right, frame is acc. along +X axis so you should apply pseudo force in -X

but i can't understand which is going where and masses should complete a circle in frame of A? ... it will if there is no gravity... and is the figure parallel to ground or what>?

 

[sgd37]

are you familiar with Lagrangian mechanics

 

[cupid.callin]

not exactyl that i have studied somthing like that but i have studied topics work&energy, circular motion, kinematics, momentum and stuff