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7: Gravitation

• 7.1: Universal Gravitation
We now dig a little deeper into a fundamental force for which we have up to now only used a simplified model for motion near the surface of the earth.
• 7.2: Kepler's Laws
The greatest achievement of Newton's law of universal gravitation is that it predicts the motions of celestial bodies. Kepler developed a set of "laws" that do the same thing, decades before Newton.
• 7.3: Energy in Gravitational Systems
We have so far focused on the force of gravity and the conservation of angular momentum for orbiting bodies. We now turn our attention to energy.

Thumbnail: A simple swinging pendulum. Image used with permission (Public domain; Lucas V. Barbosa (Kieff)).