Which term describes the point at which the entire weight of an object can be considered to act?

• A. Center of Mass
• B. Pivot Point
• C. Center of Gravity
• D. Mass Center

Answer: (C)

The weight of an object is a single gravitational force, and in many situations we can treat all that force as acting at one point. That point is the center of gravity—the location where the total weight can be considered to act. In a uniform gravity field, the center of gravity coincides with the center of mass, which is why these concepts are closely related, but the center of gravity specifically refers to where the weight acts. The other terms don’t describe where the weight acts: a pivot point is about rotation about a point, and mass center is another way to talk about where mass is concentrated, not necessarily where the weight acts. So the term that describes the point at which the entire weight can be considered to act is center of gravity.