rhs_smd.m

function f = rhs_smd(t,x,xd);
% RHS of ODE for forced SDOF spring-mass-damper system

m = 500;         % mass
c =  200;         % damping coefficient
k = 750;        % spring constant
omega = 5;       % forcing frequency (rad/s)
F0 = 2000;       % forcing magnitude

% use this for testing
if (t > 2) & (t < 15)
  F = F0;
else
  F = 0;
end


%F = F0*sin(omega*t);  % forcing function

f = (F - c*xd - k*x)/m;