%matplotlib inline
%config InlineBackend.figure_format = 'retina'
import matplotlib.pyplot as plt
import numpy as np


v = [10, 11, 12, 13, 14, 15]
g = 9.81

plt.figure(figsize=(8, 2.5))
plt.style.use('ggplot')
plt.xlim(0, 3.5)
plt.ylim(0, 12)
t = np.linspace(0, 3.5, 100)
colors = ['b', 'm',  'r', 'y', 'c', 'g','k']
for i, v_0 in enumerate(v) :
    plt.plot(t, v_0*t - 0.5*g*t**2, colors[i], lw=1)
plt.title('Motion of the ball depending on its initial velocity v$_0$', fontsize=11)
plt.legend(['{} m/s'.format(v_0) for v_0 in v], fontsize=9, fancybox=True, title='v$_0$ value')
plt.xlabel('time (in sec)', fontsize=10)
plt.ylabel('height (in meters)', fontsize=10)
plt.yticks(fontsize=8)
plt.xticks(fontsize=8)
plt.ylim(0, 12)
plt.xlim(0, 3.5)
ax = plt.gca()
ax.tick_params(axis='both', which='both',length=0)
plt.show()