function a = aaereo(v,t)
m=60;
g=9.8;
rho=1.225;
A1=1;
A2=11;

if t<10
    a=g-(1/m)*.5*rho*A1*v^2;
else
    a=g-(1/m)*.5*rho*A2*v^2;
end
return

end