Egg Drop Device Acceleration Question

[Squiller]

In science we had to build a device which, when dropped 3 stories onto cement, should not allow an egg inside inside of it to crack. One of the follow up questions says : Why should your device accelerate slightly slower than the gravitational acceleration of 9.8 m/s/s " - I can't understand why this would be ? Please help

 

[Sirus]

What other force is acting on an object falling through the air?

 

[Squiller]

other forces are the air resistance and the gravitational pull, but why would an object travel less then 9.8 m/s/s if its in freefall ?

 

[Pyrrhus]

Do the forces analysis

Using Newton's 2nd law

\sum_{i=1}^{n} \vec{F}_{i} = m \vec{a}

We get (where R is air drag the resistive force)

m \vec{g} + \vec{R} = m \vec{a}

 

[Diane_]

Remember, too - if the object is experiencing air resistance, it isn't truly in free fall.