Suppose that you loft the ball with an initial speed of v = 17.7 m/s, at an angle of θ = 50.7° above the horizontal. At this instant your opponent is d = 11.1 m away from the ball. He begins moving away from you 0.350 s later, hoping to reach the ball and hit it back at the moment that it is h = 2.15 m above its launch point. With what minimum average speed must he move? (Ignore the fact that he can stretch, so that his racket can reach the ball before he does.)