This document presents theoretical models for reactionless propulsion and an Earth gravity generator. It discusses inertial and non-inertial frames of reference and how the laws of physics vary between them. The reactionless propulsion model uses a pendulum within a rotating reference frame, where the centrifugal force vectors could potentially cancel out. Calculations determine the system energy and centrifugal forces for different parameters. The Earth gravity generator model places a bob on a spinning axis, where the centrifugal force counteracts gravity at a specific equilibrium RPM.