question_answer

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 (as shown in figure). The objects are released from rest at the position shown. Then, the tension in the cord just after release is-

A) zero                  

B) mg

C) \[\sqrt{2}\,mg\]              

D) \[mg/\sqrt{2}\]

Correct Answer: D

Solution :

\[\frac{T}{\sqrt{2}}\,\,=\,\,ma\,\,\,\,\,\,\,\,\,\,\,mg\,-\,\,\frac{T}{\sqrt{2}}\,\,=\,\,ma\] \[\therefore \,\,\,\,\,T=\frac{mg}{\sqrt{2}}\]