function dydt = aquabuoy(t,y)

% Initialize dydt vector
dydt =  zeros(4,1);

% Assign variables in equation
z1 = y(1);
z2 = y(2);
v1 = y(3);
v2 = y(4);

% Assign constants, could be passed as arguements as well
b = 1;
c = 1;
M1 = 1;  % Mass 1
M2 = 1;   % Mass 2

% Assign the forcing funciton
F = sin(pi*t);


dydt(1) = v1;
dydt(2) = v2;
dydt(3) = ( F - b*v1 - c*(z1-z2) )/M1;
dydt(4) = c*(z1-z2)/M2;