import numpy as np
import matplotlib.pyplot as plt
from scipy.integrate import odeint

mass = 0.5  # kg
kspring = 4  # N/m
cviscous = 0.4  # N s/m
eps = cviscous / (2 * mass * np.sqrt(kspring/mass))
omega = np.sqrt(kspring / mass)
eps < 1

def calc_deri(yvec, time, eps, omega):
    return (yvec[1], -eps * omega * yvec[1] - omega **2 * yvec[0])

time_vec = np.linspace(0, 10, 100)
yinit = (1, 0)
yarr = odeint(calc_deri, yinit, time_vec, args=(eps, omega))

plt.plot(yarr[:,0],yarr[:,1])
plt.show()