An object is launched directly in the air at a speed of 144 feet per second from a platform located 12 feet in the air. The motion of the object can be modeled using the function f ( t ) = − 16 t 2 144 t 12 , where t is the time in seconds and f ( t ) is the height of the object. When, in seconds, will the object reach its maximum height? Do not include units in your answer.