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Homework Help: Physics I question Skydiver falling

  1. Mar 8, 2009 #1
    1. The problem statement, all variables and given/known data

    A 79 kg skydiver can be modeled as a rectangular "box" with dimensions 25 cm x 39 cm x 1.8 m.

    What is his terminal speed if he falls feet first?


    2. Relevant equations





    3. The attempt at a solution

    So im not sure what im doing wrong, here is what i did.

    D= 1/4 av2 = .25(.25 x .39)= .020

    skydiver's weight i took from kg to N which ended up being 774.2

    then i did 774.2/.020 and did square root, and i ended up with 196.7, apparently it is saying this is not the right answer, did i do this correctly!? help! :(
     
  2. jcsd
  3. Mar 8, 2009 #2

    djeitnstine

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    Gold Member

    What formula are you using? isn't the formula for drag [tex]\frac{1}{4}\rho ADv^2[/tex] maybe [tex]\frac{1}{2}\rho ADv^2[/tex] (Its late and I feel lazy to find out which)

    where [tex]\rho[/tex] is the density of air, A is the area of the object and D is the coefficient of drag
     
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