They left off the equation but we can know it's
y(t) = h₀ - g t² / 2
That's
y(t) = 144 - 16 t²
It hits the ground when
0 = 144 - 16 t²
16 t² = 144
t² = 144 / 16 = 9
t = 3 seconds
Answer: 3 seconds
7.8m questions
10.4m answers