68 lines
No EOL
1.7 KiB
Python
68 lines
No EOL
1.7 KiB
Python
import numpy as np
|
|
from scipy.integrate import solve_ivp
|
|
import matplotlib.pyplot as plt
|
|
|
|
|
|
|
|
#Part one Diffeq
|
|
def f_part1(t, state, Me, Mm, G):
|
|
xm, ym, vx, vy = state
|
|
|
|
dvxdt = -(Me*G*xm)/((xm**2+ym**2)**(3/2))
|
|
dxmdt = vx
|
|
dvydt = -(Me*G*ym)/((xm**2+ym**2)**(3/2))
|
|
dymdt = vy
|
|
|
|
return (dxmdt, dymdt, dvxdt, dvydt)
|
|
|
|
|
|
# Initial Conditions
|
|
t_min = 0
|
|
t_max = 86400*20
|
|
numpoints = 200
|
|
t = np.linspace(t_min, t_max, numpoints)
|
|
|
|
xm0 = 384400000
|
|
ym0 = 0
|
|
vx0 = 0
|
|
vy0 = 1017.79
|
|
|
|
Me = 5.97*(10**24)
|
|
Mm = 7.35*(10**22)
|
|
G = 6.67*(10**-11)
|
|
|
|
|
|
#Solver
|
|
results = solve_ivp(f_part1, (t_min,t_max), (xm0, ym0, vx0, vy0), args=(Me, Mm, G), t_eval=t)
|
|
|
|
|
|
#Graph plotting
|
|
ax=plt.axes() # This creates some axes, so that we
|
|
ax.set_aspect(1) # can set the aspect ratio to 1 i.e.
|
|
# x and y axes are scaled equally.
|
|
ax.set_xlabel("x coordinate (m)") # Must label axes (with
|
|
ax.set_ylabel("y coordinate (m)") # units) and give
|
|
ax.set_title("Orbit of moon around earth") # plot title.
|
|
#
|
|
ax.plot(results.y[0],results.y[1]) # Make the plot
|
|
ax.legend(['Moon']) # and add a key.
|
|
plt.show()
|
|
|
|
|
|
# MyInput = '0'
|
|
# while MyInput != 'q':
|
|
# MyInput = input('Enter a choice, "1", "2" or "q" to quit: ')
|
|
# print('You entered the choice: ',MyInput)
|
|
# if MyInput == '1':
|
|
# print('You have chosen part (1): simulation of a lunar orbit')
|
|
# #
|
|
# # put your code for part (1) here
|
|
# #
|
|
# elif MyInput == '2':
|
|
# print('You have chosen part (2): earth-moon-probe system')
|
|
# #
|
|
# # put your code for part (2) here
|
|
# #
|
|
# elif MyInput != 'q':
|
|
# print('This is not a valid choice')
|
|
# print('You have chosen to finish - goodbye.') |