Question

A ball is dropped from a height of 64 feet. Its height, in feet, can be modeled by the function h(t) = -16t square + 64, where t is the time in seconds since the ball was dropped. After how many seconds will the ball hit the ground?

Answer 1

t has to be bigger than 0
the ball hit the ground so h(t) =0
-16t^(2) +64 = 0 -> 16t^2= 64 -> t^2 = 4 -> t = 2s