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Homework Help: Acceleration Question

  1. Oct 7, 2004 #1
    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 cant understand why this would be ? Please help :biggrin:
  2. jcsd
  3. Oct 7, 2004 #2
    What other force is acting on an object falling through the air?
  4. Oct 7, 2004 #3
    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 ?
  5. Oct 7, 2004 #4


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    Do the forces analysis

    Using newton's 2nd law

    [tex] \sum_{i=1}^{n} \vec{F}_{i} = m \vec{a} [/tex]

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

    [tex] m \vec{g} + \vec{R} = m \vec{a} [/tex]
  6. Oct 7, 2004 #5


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