Why hovering near the top of a waterfall of a national park of 6400 feet, a helicopter pilot drops his sunglasses. The height h(t) of the sunglasses after t seconds is given by the polynomial function h(t) = -16t(squared) + 6400. When will the sunglasses hit the ground? (in seconds). Thank you.

Answer 1

when is -16t^2 + 6400 = 0 ?

16t^2 = 6400
t^2 = 400
t = 20