\(v=\sqrt{\frac{T}{\mu}}\)
Weight of the string below the rope stretching it \(=\frac{\mu L}{2} g\).
This is equal to \(T\) at the middle.
\(\therefore \text { Velocity at middle }=\sqrt{\frac{\mu L g}{2 \mu}}\)
\(=\sqrt{\frac{g L}{2}}\)
(ગુણકારનો અચળાંક $1$ લો)