Determining Drag

http://en.wikipedia.org/wiki/Drag_(physics)

Velocity of falling object is on that same linked page too, in case you don't want the 'drag' formula.

or here;

http://en.wikipedia.org/wiki/Drag_equation

At any point in time as it falls:

1/2 rho x V2 x Cd x A

rho is the mass density of air, (.0024 slugs/cubic foot in the English system). If the fluid is not air, substitute the correct value.

Cd is the coefficient of drag of the object, which can be guessed from reference to other objects (with, for example, a finless torpedo being about .06, a Prius being .26, a pickup truck being .4, a cube being about 1) or can be calculated with a CFD program (or by hand by someone with incredible patience and fortitude -- I'd guess this might take a year to do it as thoroughly as a 3d cfd program will), or can be found in a wind tunnel.

A is the frontal area, the area projected in the direction of motion.

V is the velocity, in appropriate units to match the mass density units (e.g, fps in English units.

The force causing acceleration will be the weight of the object, minus the drag at each increment in time. At some point, drag will equal weight, and the terminal speed will have been reached.

A spreadsheet allows you to easily look at what happens at each increment, which you can make as small or large as you want, just by copying the formulas as many times as you'd like, 10 being a reasonable minimum.

go to school !

For math, or English?

both

Thanks,This helps me a lot .I stil have to learn more about drag seeing as i'm stil in school...But once again thank you for all the effort that you have put into your reply on my qeustion.