A bullet of 10 g, moving with velocity $$v$$, collides head-on with the stationary bob of a pendulum and recoils with velocity 100 m s$$^{-1}$$. The length of the pendulum is 0.5 m and mass of the bob is 1 kg. The minimum value of $$v$$ in m s$$^{-1}$$, so that the pendulum describes a circle. (Assume the string to be inextensible and g = 10 m s$$^{-2}$$)