%% simulation ODE   dv/dt = (F - k * v )/ m;

% Constant
m = 1000;  % mass

% Parameters
k = 50; 
F = 2000;

% Variable 
v0 = 20;

tspan = [0, 200];

% ODE equation 
dvdt = @ (t,v) (F - k * v )/ m;

% solution 
[tSol, vSol] = ode45(dvdt, tspan, v0);

plot(tSol, vSol, 'b-', 'LineWidth', 3);
title('velocity')