JEE Advanced Model Paper 12 with solutions for online practice

A wheel has eight equally space, very thin spokes of length 30 cm. It is rotating about axis OO1 which is perpendicular to its plane and passing through centre, with 2.5 rps. We want to pass a 20 cm long arrow parallel to the axis and without hitting any spoke. What should be the minimum velocity of the arrow? [Assumed as initially the arrow is just ready to poss]