How to solve coupled second order ODE?

Hello, I want to solve this system of equations (body falling with air resistance) to be able to blot x and y.

With initial conditions:

Does anyone have any pointers? Reading the documentation seems I need to write them as first order equations, but as I do not have de explicit function, I don't know how to obtain x and y.

Thank you!

[Torsten]

Initial conditions ?

[Juan Pedro Martinez]

Hello, thanks for your reply. You are right, I was jsut focusing on programming and forgot the math. I edited the question so the information is visible.

Answer 1

[Torsten]

b = 0.1;
fun = @(t,y)[y(2);-b*y(2)*sqrt(y(2)^2+y(4)^2);y(4);-b*y(4)*sqrt(y(2)^2+y(4)^2)];
y0 = [0;44.5;80;0];
tspan = [0,10];
[T,Y] = ode45(fun,tspan,y0);
plot(T,[Y(:,1),Y(:,3)])