function wprime = parachuteODE2(t, w)
g = 9.8  ; % gravity = 9.8 m/sec^2
cD = 10  ; % coef of Drag = 10 kg/sec
m  = 70  ; % mass = 70 kg
v = w(1) ;
y = w(2) ;

vprime = g - (cD*v) / m;
yprime = v;
wprime = [vprime; yprime];