Two beads of equal masses `m` are attached by a string of length `sqrt2a` and are free to move in a smooth circular ring lying in a vertical plane as shown in figure. Here a is the radius of the ring. Find the tension and acceleration of `B` just offer the heads are released to move.

Options

A. Zero
B. mg
C. `sqrt(2)mg`
D. `mg//sqrt(2)`

Answer

D

Explanation

As shown in fig. from FBD of A,
`T cos 45^(@)=ma` …(i)
From FBD of B:
`Mg-T cos 45^(@)=ma`..(ii)

From (i) and (ii) we get `T=mg//sqrt(2)`.