Tiro parabolico

import numpy as np
import matplotlib.pyplot as plt
import math

N   = 20
t   = np.zeros(N)
x   = np.zeros(N)
y   = np.zeros(N)

g   = 9.8
v0  = 100.0
ang = 45.0

x0  = 0.0
y0  = 0.0
v0x = v0*math.cos(ang*(math.pi/180))
v0y = v0*math.sin(ang*(math.pi/180))

ti = 0.0
tf = 10.0
dt = (tf-ti)/N
for it in range(0,N):
    t[it]=ti+it*dt
    x[it]=x0+v0x*t[it]
    y[it]=y0+v0y*t[it]-0.5*g*t[it]*t[it]

plt.plot(x,y,'-o')
plt.show()

plt.plot(x,y,'-o',label='45grados')
plt.title("Tiro parabolico")
plt.xlabel("x")
plt.ylabel("y")
plt.grid()
plt.legend()
plt.show()

plt.plot(x45,y45,'-ob',label='45grados')
plt.plot(x30,y30,'-or',label='30grados')
plt.plot(x15,y15,'-og',label='15grados')
plt.title("Tiro parabolico")
plt.xlabel("x")
plt.ylabel("y")
plt.grid()
plt.legend()
plt.show()