Skydiving

[sorra54]

1. The problem statement, all variables and given/known data

I'm writing an assignment about Extreme Sports, including Skydiving and Bungee Jump,
and since I'm not that good at physics, I was hoping that maybe some of you guys could help me!

I am to analyze a skydiver, and chop the fall into phases, and use both math and physics to describe what happens at each phase.
This is what I've come up with so far.

A skydiver will go through 3-5 phases,
phase 1. a = g
phase 2. F gravity > F air
phase 3. F gravity = F air
phase 4. Parachute opens, F air > F gravity
phase 5. F air = F gravity

2. Relevant equations

My question to you guys is first of all, at the page http://ffden-2.phys.uaf.edu/211_fall2002.web.dir/DaneLenakerSkydiving/drag.htm under the hyperlink that says drag, you'll find an animation at the bottom of this page. I says that a = Fnet/m.
Is that really an equation for the acceleration a?

Second of all, i have come across an equation that will calculate the drag for,
F drag = 0.5*Cd*(greek letter rho)*A*v^2, how will i know what speed his traveling with at a given time, and what the cross-sectional area, A, is for a human, and most important of all, the drag coefficient for a human, and later a parachute?


3. The attempt at a solution

No solutions that are worth posting so far, sorry !

[nickjer]

That is the equation for the skydiver's acceleration (a = F_net/m, is the equation for instantaneous acceleration of basically anything with a net force applied to it). To find his speed at any given time you will need to know calculus. To find cross-sectional area, take a logical guess. Look up drag coefficients in tables.

Also, I believe you can leave off phase 1. Since there is still air when he initially jumps. Unless phase 1 is him sitting on the plane still, which seems odd that it is a phase of the jump.