Atoy rocket blasts straight up off the gound with an initial velocity of 50 ft/s. how long will the rocket remain in the air? use the formula h= -16t^2+50t , where h is the height of the rocket in feet and t is the time in seconds after liftoff. assume no air resistance, and that the rocket has no propelling force after liftoff. round your answer to the nearest tenth. a. 1.4 seconds b. 2.8 seconds c. 3.1 seconds d. 4.2 seconds