During halftime of a basketball game, a sling shot launches T-shirts at the crowd. A T shirt is launched from a heigh of 4 feet with an initial upward velocity of 72 feet per second. Use the equation h(t)=-16t^2+72t+4, where t is time in seconds and h(t) is height. How long will it take the T-shirt to reach its maximum height? What is the maximum height?