find the tension in the cord just after release is

Question

Two objects A and B, each of mass m, are connected by a light inextensible string. They are restricted to move on a frictionless ring of radius R in a vertical plane. The objects are released from rest at the position shown. Then the tension in the cord just after release is

Answer 1

Let mass A move with acceleration 'b' and mass B move with acceleration 'a'.

directions of 'a' and 'b' are different but magnitude of 'a' and 'b' are same. 

Since the length of the rope AB is same 

acos45=bcos45 

a=b 

Also Tsin45=mb------(1) for A 

mg−Tsin45=ma-----(2) for B 

2ma=mg

=>a=g/2 

Substituting in (1)