If an object is projected from a height of 336 ft with an initial velocity of 64 ft per sec, its height after t seconds is given by the following equation h=-16t + 64t+336 Use this information to answer parts (a) and (b) below. (a) After how many seconds is the height 400 feet? (Hint: Let h=400 and solve.) The height is 400 feet after second(s).