Tag: mass defect

• Relativistic Mechanics: What the Four-Momentum Says About E = mc²Newtonian momentum conservation fails between inertial frames. Building proper time, four-velocity and four-momentum repairs it, yielding E = γmc², E² = (pc)² + (mc²)², and non-additive mass.PhysicsRelativityUndergraduatespecial relativityfour-momentumrest energymass-energy equivalencemass defect~35 min