ASTRON 1101 Lecture Notes - Lecture 10: Parabolic Trajectory, Semi-Major And Semi-Minor Axes, Orbital Period
17 Sep 2016
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Document Summary
Newton showed kepler"s laws can be derived from newton"s 3 laws of motion and his law of gravity. Newton also showed kepler"s laws can be generalized to any two bodies moving under the influence of their mutual gravity. Kepler"s 1st: planetary orbits are ellipses, with the sun at one focus. Newton: orbits are conic sections, with the center of mass at one focus. Conic sections are curves formed by slicing a cone: closed curves. An object on a closed orbit (circle or ellipse) is bound to the object it is orbiting. An object on an open orbit (parabola or hyperbola) is unbound. After one close passage, it escapes the system. You are at a distance r from an object of mass m. the type of orbit you are on depends on your orbital speed. Circular speed = speed needed to be on a circular orbit. Escape speed = minimum speed needed to be on an unbound orbit.
