A ball of mass m = 7.8 kg,  attached to the pole using a string of length L = 1.31 m, is smacked so that it goes in a circle around as shown below and in this video (https://www.youtube.com/watch?v=x5tLrVT3sxg).  Unlike the video, in this question, the ball travels in a circle lying in a plane parallel to the ground.  With what constant speed, v (m/s), must the ball be moving so that the string makes an angle θ = 23 degrees with respect to the vertical?