A helicopter is ascending vertically with a speed of 1.00 m/s. At a height of 70 m above the Earth, a package?

Question

A helicopter is ascending vertically with a speed of 1.00 m/s. At a height of 70 m above the Earth, a package is dropped from a window. How much time does it take for the package to reach the ground? [Hint: The package's initial speed equals the helicopter's.]
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Answer 1

use the equation of motion:

d = v0t + 1/2at^2
where d = -70
v0 = +1
a = -9.8
so we have -70 = t -4.9t^2
or
4.9t^2 - t - 70 = 0.
Use the quadratic formula with a = 4.9, b = -1,c = -70
to get
t = 1/9.8 * (1 + sqrt(1+4*4.9*70)) = 3.88 seconds

Answer 2

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