# Physics

A helicopter is ascending vertically with a speed of 5.20 m/s. AT the height of 125m above the earth, a package is dropped from a window.How much time does it take for the package to reach the ground.

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1. If release occurs at t=0, the vertical height ot the package after that, in meters, is
y = 125 + 5.2 t -4.9 t^2
(The 4.9 is g/2, and g is the acceleration of gravity in units of m/s^2)
Solve the equation y = 0 and you will get the time that it his the ground. It is a quadratic equation with two roots. Take the positive one.

t = [-5.2 -sqrt(5.2^2 +4*125*4.9)]/(-9.8)
= 5.61 seconds

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2. thank you so much!

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