Finding the trajectory of a ball

Hello, I'm trying to find the trajectory of a ball thrown in the air. And while trying to implement the code into MATLAB, I get errors with it.

function yp = fball(t,y)
g = 9.81; % Gravitational field
c = 0.479; % Scaled drag coefficient
w = 40; % Horizontal wind speed
% Unpack for position and velocity
x = y(1:2);  %I get an error here telling that i dont have enough input arguments
v = y(3:4);  %I get an error here telling that i dont have enough input arguments
% Velocity relative to wind
vv = v;
vv(1) = vv(1)-w;
% Compute for  acceleration
a = -c*norm(vv)*vv;
a(2) = a(2)-g;
% Return
yp = [v; a ];
% −− Sanity check trajectories computed with and without drag −−
theta = pi/3;
v0 = s*[cos(theta); sin(theta)];
% Computing the reference trajectory (absent air resistance )
x(y) = s*cos(theta)*t
y(t) = -g*t^2/2 + s*sin(theta)*t
% up to time tfinal = 2∗s∗sin(theta)/g
tfinal = 2*v0(2)/g;
tref = linspace(0,tfinal );
xref = v0(1)*tref;
yref = (v0(2)-g/2*tref).*tref;
% Compute the same reference trajectory with ode45
y0 = [0; 0; v0];
refopt = opt;
refopt .c = 0;
[tout,yout] = ode45(@(t,y) fball(t,y ), tref , y0);
% Compute a similar trajectory with air drag on (no wind)
dopt = opt;
dopt.w = 0;
[toutd,youtd] = ode45(@(t,y) fball(t,y), tref , y0);
% Visually comparing solutions for drag and no drag
plot(xref, yref , ' r: ' , youtd (:,1), youtd (:,2), 'b-');
legend('No drag', 'Drag');
end

Can someone help me with this problem?

[Image Analyst]

I formatted your code for you. You can do this next time by clicking the CODE icon after you paste and highlight the code. What values did you pass in for t and y?

[Nicolae Lungu]

arguments: the time t and the vector y(t).....

Answer 1

[Steven Lord]

Do not call ode45 with fball as the ODE function from within fball itself! That way lies (at best) a recursion error. Call ode45 from outside fball.

If after making that change you're still receiving errors, please show us your updated code (with the ode45 call moved out of fball) and the full and exact text (all the text displayed in red and/or orange in the Command Window) of any errors and/or warnings you received when running your code.