Here is an outline to get you started:
---> constant stuff goes here <---
t = 0:1:20; % The time values (s)
n = numel(t); % The number of time values
v = zeros(1,n); % The velocity values (m/s)
v(1) = 20; % The initial velocity value (m/s)
for k=1:n-1 % For each subsequent time value
something = _____; % The delta-velocity stuff based on your equation and the time t(k)
v(k+1) = v(k) + something; % The Euler step
end
So in your case, you need to fill in the "something" stuff. Set up your constants etc at the beginning of your code. Then inside the loop, you will need an if-test based on the current value of t(k) to determine the value of the drag coefficient to use in your "equation". You should double check your listed equation above since it doesn't look quite right (e.g., the *t part).
