How to take data from a loop and add it into a function?

Basically i'm using [rho, P, T, ZorH] = stdatmo(...) which gives air density, pressure, temperature, and altitude. I need these in 1 second increments until P reaches .09 atm (the point at whitch my balloon will reach its max volume considering temperature is constant.)

The only problem is that stdatmo goes off of altitude instead of time and i have no idea how to figure out the acceleration in each time incremeant to plug it into stdatmo. I know acceleration is equal to the net force divided by the mass and the inital acceleration is 3.74m/s^2 but i have no idea where to go from there. Heres what i have so far:

%Final Project: David Deertz

%Tracking a balloon's vertical and horizontal movement carrying a 
%package as it travels down wind from the drop location. Winds are 
%a constant speed of 15mph. 

%Constants
Mballoon  = 4.349; %kg 
R         = .0821; %Gas Constant, L*atm/mol*K
MaxVolume = 41890; %L 
Fgrav     = 32.85; %N 
P0        = 1; %atm
V0        = 4189; %L
T        = 273.15; %K
n_helium  = (P0*V0)/(R*T0);
BurstPressure = (n_helium*R*T)/(MaxVolume);

I know i dont have much but it is for a project and its really confusing me. I'm a super beginner when it comes to matlab. Thanks for any help i'd love to chat in comments with some of you to get ideas.

[per isakson]

stdatmo &nbsp is that STDATMO: Standard Atmosphere Function by Sky Sartorius ?