This document discusses momentum and how it relates to inertia. It explains that momentum is calculated as mass times velocity, and that applying a net force over time (impulse) is needed to change an object's momentum. Examples are given of how increasing force, time of force application, or both can increase an object's momentum, while decreasing force over a longer time or increasing force over a shorter time can decrease momentum. The document also covers Newton's third law of motion and how momentum is conserved in collisions and interactions between objects within a system.