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class Planet(VMobject): |
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def __init__(self, |
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sun:VMobject=None, |
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ax:CoordinateSystem=None, |
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color = BLUE, |
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radius =0.1, |
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mass = 6e24, |
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pos = np.array([150e9,0,0]), |
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vel = np.array([0,30e3,0]), |
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G = 6.67e-11, |
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speed_factor = 24*60*60*20 |
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): |
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super().__init__() |
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self.become(Dot(point=ax.c2p(*pos), color=color, radius=radius)) |
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self.mass = mass |
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self.vel = vel |
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self.ax = ax |
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self.sun = sun |
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self.G = G |
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self.speed_factor = speed_factor |
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self.add_updater(self.updater) |
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|
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def updater(self, obj, dt): |
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if self.sun is not None: |
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dvec = self.ax.p2c(self.sun.get_center())-self.ax.p2c(obj.get_center()) |
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a = dvec*self.G*self.sun.mass/(np.linalg.norm(dvec)**3) |
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obj.vel = obj.vel + a*dt*self.speed_factor |
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obj.shift(self.ax.c2p(*(obj.vel*dt*self.speed_factor))) |
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|
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class orbit(Scene): |
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def construct(self): |
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ax = ThreeDAxes( |
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x_range=[-200e9,200e9,50e9], |
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y_range=[-200e9,200e9,50e9], |
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z_range=[-200e9,200e9,50e9], |
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x_length=8, |
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y_length=8, |
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z_length=8, |
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tips=False |
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) |
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G = 6.67e-11 |
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sun = Planet( |
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sun = None, |
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ax = ax, |
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color = YELLOW, |
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radius = 0.2, |
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mass = 2e30, |
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pos = np.array([0,0,0]), |
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vel = np.array([3000,0,0]), |
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) |
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earth = Planet( |
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sun = sun, |
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ax=ax, |
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radius=0.1, |
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color=BLUE, |
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mass=6e24, |
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pos = np.array([150e9,0,0]), |
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vel = np.array([3000,30000,0]), |
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) |
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|
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bluetrace = TracedPath(earth.get_center, stroke_width=1, stroke_color=BLUE) |
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|
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self.add(sun,earth,bluetrace) |
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self.wait(50) |
