A pendulum of length 2 m consists of a wooden bob of mass 50 g. A bullet of mass 75 g is fired towards the stationary bob with a speed v. The bullet emerges out of the bob with a speed $\frac{v}{3}$ and the bob just completes the vertical circle. The value of v is ________ $\mathrm{ms}^{-1} .\left(\right.$ if $\left.\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2\right)$