a person in a hot air balloon ascending vertically at a constant rate of 12mm/s drops a rock over the side when the balloon is 40m above the ground how long will it take the rock to reach the ground

Answer 1

12 mm/s = .012 m/s = Vi initial speed up

h = Hi + Vi t - 4.9 t^2

0 = 40 + .012 t - 4.9 t^2

Solve quadratic for t