Answer:
a. 144 ft
b. 5 s
Step-by-step explanation:
h = -16t² + 64t + 80
a. This is a parabola, so the maximum height is at the vertex.
t = -64 / (2 × -16)
t = 2
h = -16(2)² + 64(2) + 80
h = 144
The apple reaches a maximum height of 144 ft.
b. 0 = -16t² + 64t + 80
0 = t² − 4t − 5
0 = (t + 1) (t − 5)
t = -1 or 5
t must be positive, so it takes 5 seconds to reach the ground.
