A helicopter is ascending vertically with a speed of 5.60m/s. At a hight of 115m above the earth, a package is dropped from a window. How much time does it take for the package to reach the ground.

Answer 1

From Vf = Vo - 9.8t, 5.6 = 0 - 9.8t or t = .571sec. to zero verical velocity and maximum height.

From h = Vot - 4.9t^2, h = .56(.571) - 4.9(.571)^2 or h = 1.597 m upward from the 115m drop point for a total height of 116.56m.

Again, from h = Vot + 4.9t^2, the time to reach the ground derives from
116.56 = 0(t) + 4.9t^2 or t = 4.85 sec.