While hovering near the top of Ribbon Falls in Yosemite National park at 1600 feet, a helicopter pilot accidentally drops his sunglasses. The height h(t) of the sunglasses after t second is given by the polynomial function h(t)=-16t^2+1600. When will the sunglasses hit the ground? (Hint: Let the height, h(t), be 0 and solve for t.)