Method acc

Lib/turtledemo/planet_and_moon.py:50–56

(self)

        self.a = self.acc()
        self.v = self.v + 0.5*dt*self.a
    def acc(self):
        a = Vec(0,0)
        for planet in self.gravSys.planets:
            if planet != self:
                v = planet.pos()-self.pos()
                a += (G*planet.m/abs(v)**3)*v
        return a
    def step(self):
        dt = self.gravSys.dt
        self.setpos(self.pos() + dt*self.v)