- Gravity Integral
- This work shows that outside of any spherically symmetric mass
distribution (such as a planet) the gravity field is identical to that
of a point particle with equal mass. It also shows that
*inside*any spherically symmetric mass shell (such as a planet with a concentric spherical cavity), gravity is zero throughout the interior.

- This work shows that outside of any spherically symmetric mass
distribution (such as a planet) the gravity field is identical to that
of a point particle with equal mass. It also shows that
- Projectile Orbit
- A projectile in a uniform gravity field follows a parabolic path. But according to Keplerâ€™s First Law the projectile is actually orbiting the center of the Earth in an ellipse. You can show that these curves are the same with a little algebra.

- Multiparticle Dynamics
- An external force may accelerate and rotate a system of particles.

*Last modified in December 2023 by Archie Paulson.*