How Do You Achieve Equilibrium in a Dual-Radius Pulley System?

[yopy]

my problem is the one shown above. In all honesty i do not know how this system works since a pulley with two radii's has two different cables running through it. Does anyone know where i need to start at with this problem?

 

[tiny-tim]

Hi yopy!

Hint: if A and B were at the same radius, then the tension in ropes 1 and 2 would be the same … can you see why?

ok, now use the same principle to find the actual relationship between the tensions.

 

[rl.bhat]

From he figure, I presume that pulleys 1 and 2 are combined one with radii 100 mm and h300 mm. If TA and TB are the tensions in rope A and B, then what should be the condition so that the pulley system 1 and 2 will remain in equilibrium?
What should be the condition that the pulley 4 shall have neither rotational motion nor the translational motion.