# Coefficient of Drag

1. Apr 13, 2004

### Hazarrd

Im doing research on skydiving and I am trying to find out how much drag is created on different jumps. I have different velocities for each of the jumps.

D = Cd ((rV^2)/2)A

That is the equation I am using. r is air density which im using 1.2 kg/m^3. V is the velocity. And ive measured the skydivers approximate area (A) to be .871 square meters. How do I find Cd (Drag coefficient)? Is this a constant? Is there somewhere I can get some more information on what Cd would be? Thanks!

2. Apr 14, 2004

### FUNKER

you have to calculate the coeffiecent on a basis where that is the unknown and then just re arrange, and to my belief the drag co-efficient is a constant that varies with the fluid the object is travelling in be it air water or honey.

3. Apr 14, 2004

### Stingray

Cd depends mostly on the shape of the object, and very weakly on something called Reynold's number. There's no simple way to calculate Cd, so its usually just measured experimentally. Here are some examples with simple shapes: http://www.insideracingtechnology.com/tech102drag.htm.

Last edited by a moderator: Apr 20, 2017