Kepler formulated three planetary-motion laws {Kepler's laws} {Kepler laws}.
first law
Radius from orbiting body to Sun sweeps out equal areas in equal times, because velocity is slow at large radius and fast at small radius.
second law
If object in orbit moves closer, speed increases as potential energy changes to kinetic energy and moves object back outward. If object in orbit moves farther away, speed decreases as kinetic energy changes to potential energy and moves object inward.
If spinning object becomes more compact, radius decreases and speed increases as potential energy changes to kinetic energy. If spinning object expands, radius increases and speed decreases as kinetic energy changes to potential energy.
third law
Acceleration cubed is directly proportional to time squared, because acceleration is highest at greatest curvature point, where velocity is highest.
Physical Sciences>Physics>Dynamics>Rotation>Orbit
5-Physics-Dynamics-Rotation-Orbit
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Date Modified: 2022.0224