Tension between two objects hanging

[lizzyb]

http://img329.imageshack.us/my.php?image=serway5e1619asinbookjn5.jpg"

How do we determine the tension of the string in the middle of the two objects? Let the tensions be T_1, T_2, and T_3, left to right:

I tried

$$\sum F_x = T_2 - \cos \theta T_1 = 0$$
$$\sum F_y = \sin \theta T_1 - mg = 0$$

for the other object it is similar. Is there something wrong with this? I can calculated T_2 without regard to the other object. Should I not include both the objects in F_y? thanx!

 

[radou]

If T2 is the tension in the middle string, this looks just okay.

 

[lizzyb]

ok, got it! thanx! :-)