Professional Ski Instructors Of America (PSIA) Level 2 Practice Exam

The center of mass is the point where the body's mass can be treated as if it's all concentrated. It’s defined as the weighted average position of every bit of mass in the body, so it encapsulates how the mass is actually distributed in space. In a uniform gravitational field, the center of gravity lines up with the center of mass, so the weight and the mass effectively act through the same point. That makes balance, rotations, and motion easier to analyze, which is why this concept is central in skiing technique and physics of bodies in motion. Center of gravity describes where the gravitational force acts, which matches the center of mass only when gravity is uniform. A pivot point is simply where rotation occurs, not a representation of mass distribution. A balance point is a casual term for where something balances, not a precise physics concept.