Last active
May 15, 2022 16:27
-
-
Save bhuron/e740c6ab1bcd4c07bc491b558f7a8fcf to your computer and use it in GitHub Desktop.
DTL n°10
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
{ | |
"cells": [ | |
{ | |
"metadata": { | |
"trusted": true | |
}, | |
"cell_type": "code", | |
"source": "import math\nfrom fractions import Fraction", | |
"execution_count": 1, | |
"outputs": [] | |
}, | |
{ | |
"metadata": {}, | |
"cell_type": "markdown", | |
"source": "La vitesse moyenne de John Glenn qui a effectué trois fois une orbite de 46 667 km \nen cinq heures (en km/h) est simplement :\n$$vitesse = \\frac{46667 \\times{} 3}{5}$$\n" | |
}, | |
{ | |
"metadata": { | |
"trusted": true | |
}, | |
"cell_type": "code", | |
"source": "average_speed = (46667 * 3) / 5\nprint(f'La vitesse moyenne de John Glenn était de {average_speed} km/h')", | |
"execution_count": 2, | |
"outputs": [ | |
{ | |
"output_type": "stream", | |
"text": "La vitesse moyenne de John Glenn était de 28000.2 km/h\n", | |
"name": "stdout" | |
} | |
] | |
}, | |
{ | |
"metadata": {}, | |
"cell_type": "markdown", | |
"source": "On a la vitesse de la lune en m/s. Pour connaître la distance quotidienne (en km), on a :\n\\begin{align*}\ndistance/jour &= 1023 \\times{} 10^{-3}\\times{} 3600 \\times{} 24\\\\\ndistance/jour &= 88387,2\n\\end{align*}\n\nCalculer la distance R (en kms) entre la lune et le centre de la Terre (en assumant une orbite circulaire)\nrevient à résoudre :\n\\begin{align*}\nP &= 2\\pi{}R\\\\\nR &= \\frac{P}{2\\pi{}}\n\\end{align*}\n\nOr, vu que la lune tourne autour de la Terre en 27,3 jours, on a :\n\\begin{align*}\nP &= distance/jour \\times{} 27,3\\\\\nP &= 88387,2 \\times{} 27,3\\\\\nP &= 2412970,56\n\\end{align*}\n\nAinsi,\n\\begin{align*}\nR &= \\frac{P}{2\\pi{}}\\\\[10pt]\nR &= \\frac{2412970,56}{2\\pi{}}\n\\end{align*}\n\nCe qui place la distance entre la lune et le centre de la Terre aux alentours\nde 384 000 kms." | |
}, | |
{ | |
"metadata": { | |
"trusted": true | |
}, | |
"cell_type": "code", | |
"source": "vitesse_lune = 1023 # m/s\ndistance_quotidienne = vitesse_lune * 3600 * 24 # distance parcourue en 1 jour (m)\nprint(f\"La lune parcourt chaque jour {distance_quotidienne * pow(10, -3)} kms.\")\nlongueur_orbite = distance_quotidienne * 27.3 # en m\nrayon = longueur_orbite * pow(10, -3) / (2 * math.pi) # kms\nprint(f\"La distance entre la lune et le centre de la Terre est dans les alentours de {int(round(rayon, -2))} kms.\")", | |
"execution_count": 3, | |
"outputs": [ | |
{ | |
"output_type": "stream", | |
"text": "La lune parcourt chaque jour 88387.2 kms.\nLa distance entre la lune et le centre de la Terre est dans les alentours de 384000 kms.\n", | |
"name": "stdout" | |
} | |
] | |
}, | |
{ | |
"metadata": {}, | |
"cell_type": "markdown", | |
"source": "Pour garder les garçons en orbite, Elisabeth doit équilibrer les deux forces G et F, ce qui\nrevient à résoudre :\n\n\\begin{align*}\nG &= F \\\\\n\\frac{A_1 \\times{} A_2}{R^2} &= \\frac{A_1 \\times{} v^2}{R}\\\\\n\\frac{A_1 \\times{} A_2}{R^2} {\\color{red}\\times{} \\frac{R^2}{A_1}} &= \n \\frac{A_1 \\times{} v^2}{R} {\\color{red}\\times{} \\frac{R^2}{A_1}} \\\\\nA_2 &= Rv^2\\\\\nv^2 - \\frac{A_2}{R} &= 0\\\\\n\\end{align*}\n\nSi on remplace $A_2$ et $v$ par les valeurs données dans l'énoncé, on obtient :\n\\begin{align*}\nv^2 - \\frac{25}{9} &= 0\\\\\nv^2 - \\left(\\frac{5}{3}\\right)^2 &= 0\\\\\n\\left(v - \\frac{5}{3}\\right)\\left(v + \\frac{5}{3}\\right) &= 0\\\\\n\\end{align*}\n\nOr un produit de facteurs est nul si et seulement si un de ses facteurs au moins\nest nul.\n\nAinsi, on a :\n\\begin{align*}\n\\left(v - \\frac{5}{3}\\right) &= 0 \\qquad \\text{ou} \\qquad &\\left(v + \\frac{5}{3}\\right) &= 0\\\\\nv &= \\frac{5}{3} &v = -\\frac{5}{3}\n\\end{align*}\n\nLa vitesse est positive. Elisabeth devra donc repousser le garçon à $\\frac{5}{3}$ m/s. Vérifions. \n\n" | |
}, | |
{ | |
"metadata": { | |
"trusted": true | |
}, | |
"cell_type": "code", | |
"source": "a1 = 12 # Peu importe la valeur en vérité, tant qu'elle est non nulle\ndef gravity(a2, r, v):\n return Fraction((a1 * a2), pow(r, 2))\n\ndef repulsion(a2, r, v):\n return Fraction((a1 * pow(v, 2)), r)", | |
"execution_count": 4, | |
"outputs": [] | |
}, | |
{ | |
"metadata": { | |
"trusted": true | |
}, | |
"cell_type": "code", | |
"source": "gravity(25, 9, Fraction(5, 3)) == repulsion(25, 9, Fraction(5, 3))", | |
"execution_count": 5, | |
"outputs": [ | |
{ | |
"output_type": "execute_result", | |
"execution_count": 5, | |
"data": { | |
"text/plain": "True" | |
}, | |
"metadata": {} | |
} | |
] | |
} | |
], | |
"metadata": { | |
"interpreter": { | |
"hash": "b0fa6594d8f4cbf19f97940f81e996739fb7646882a419484c72d19e05852a7e" | |
}, | |
"kernelspec": { | |
"name": "python3", | |
"display_name": "Python 3 (ipykernel)", | |
"language": "python" | |
}, | |
"language_info": { | |
"name": "python", | |
"version": "3.9.10", | |
"mimetype": "text/x-python", | |
"codemirror_mode": { | |
"name": "ipython", | |
"version": 3 | |
}, | |
"pygments_lexer": "ipython3", | |
"nbconvert_exporter": "python", | |
"file_extension": ".py" | |
}, | |
"gist": { | |
"id": "", | |
"data": { | |
"description": "dtl-10.ipynb", | |
"public": true | |
} | |
} | |
}, | |
"nbformat": 4, | |
"nbformat_minor": 2 | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment