Two uniform ropes having linear mass densities `m` and `4m` are joined to form a closed loop. The loop is hanging over a fixed frictionless small pulley with the lighter rope above as shown in the fig. (in the figure equilibrium position is shown). Now if point `A` (joint) is slightly displaced in downward direction and released, it is found that the loop performs SHM with the period of oscillation equal to `N`. Find the value of `N` (take `l=(150m)/(4pi^2)`,`g=10(m)/(s^2)`).