# 7: Gravitation

- Page ID
- 18421

- 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)).