The center of gravity is the point where the weight of an object appears to act, but it does not represent the actual point of force application for each particle. Gravity acts on all particles within the object equally, leading to the concept of the center of gravity being a point of balance. When a force is applied in line with the center of gravity, it generates no torque, allowing for stable equilibrium. Additionally, a moment refers to the turning effect produced by a force applied at a distance from a pivot point. Understanding these concepts is crucial for analyzing forces and motion in physics.