Physics
posted by Jen .
A helicopter is ascending vertically with a speed of 9.00 m/s. At a height of 90 m above the Earth, a package is dropped from a window. How much time does it take for the package to reach the ground?

d = Vo*t + 0.5*9.8t^2 = 90 m,
9*t + 0.5*9.8t^2 = 90,
9t + 4.9t^2  90 = 0,
4.9t^2 + 9t  90 = 0,
Solve for t using quad. Formula & get:
t = 3.46 s.