A toy rocket is shot vertically into the air from a launching pad 4 feet above the ground with an initial velocity of 136 feet per second. The height h, in feet, of the rocket above the ground at t seconds after launch is given by the function h(t) = - 16t+ 136t+ 4. How long will it take the rocket to reach its maximum height? What is the maximum height? The rocket reaches its maximum height at second(s) after launch. (Simplify your answer.)