Reduced mass, defined as μ = m1*m2/(m1+m2), is primarily used in problems involving two-body systems, particularly in physics contexts like orbital mechanics and collisions. It simplifies calculations by allowing the analysis of two interacting bodies as a single entity with reduced mass, especially when examining their motion relative to their center of mass. Common applications include gravitational interactions, elastic and inelastic collisions, and systems where one mass is significantly smaller than the other. The concept is closely tied to the conservation of momentum and energy principles in these scenarios. For detailed examples and further understanding, consulting resources like the Wikipedia article on reduced mass is recommended.