William is preparing to throw a tennis ball off the roof of the john hancock center, 1130 feet above street level. stephanie is waiting to catch the ball on the rooftop of the neighbouring water tower place, 830 feet above street level. william throws the ball, which leaves his hand with an upward velocity of 46 feet per second, and travels in a parabolic path. stephanie catches the ball exactly 6.0 seconds after it is thrown.

stephanie uses a machine to launch the ball back up to william, who catches it exactly 6.0 seconds after it is launched. what is the upward velocity in feet per second of the ball as it leaves the launcher?