An astronaut on the moon throws a baseball upward. the astronaut is 6ft, 6 in. tall and the initial velocity of the ball is 30 ft per second. the height s of the ball in feet is given by the equation 2.7 t^2 + 50 + 6.5 where t is the number of seconds after the ball is thrown. After how many seconds is the ball 12 ft above the moons surface?