The height h (in feet) of an object after it is launched given by the function h = -16t^2 + v0t+h0 where v0 is the initial vertical vole city, h0 is the initial height of the object, and t is the time (in seconds) after the object is launched . A toy rocket is launched from the ground level with an initial vertical velocity of 96 ft/s. After how many se done will the rocket hit the ground ?