Example 1.5: Semi-vertical angle of the conical section of a funnel is 370. There is a small ball kept inside the funnel. On rotating the funnel, the maximum speed that the ball can have in order to remain in the funnel is 2 m/s. Calculate inner radius of the brim of the funnel. Is there any limit upon the frequency of rotation? How much is it? Is it lower or upper limit? Give a logical reasoning. (Use g = 10 m/s2 and sin 370 = 0.6)