Physics I question Skydiver falling

[bpatel4116]

Homework Statement

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?

Homework Equations

The Attempt at a Solution

So I am not sure what I am 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! :(

 

[djeitnstine]

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

where $$\rho$$ is the density of air, A is the area of the object and D is the coefficient of drag