What tangential speed v must the bob have so that it moves in a horizontal circle

(Figure 1) A bob of mass m = 0.300 kg is suspended from a fixed point with a massless string of length L = 23.0 cm . You will investigate the motion in which the string traces a conical surface with half-angle ? = 19.0 °. What tangential speed v must the bob have so that it moves in a horizontal circle with the string making an angle 19.0 ° with the vertical? Express your answer numerically in meters per second.