What is weight? How is it related to mass and gravity?

• A. Weight is the gravitational force on an object, calculated as W = m g.
• B. Weight is the distance an object falls.
• C. Weight equals velocity times mass.
• D. Weight is the mass of an object.

Answer: (A)

Weight is the gravitational force acting on a body. It depends on both how much matter the object has (its mass) and how strong gravity is where it is located. The relationship is W = m × g, where m is mass and g is the acceleration due to gravity. Mass stays the same no matter where you are, but gravity can change, so weight changes with location (for example, a person weighs less on the Moon than on Earth even though their mass is the same). On Earth, g is about 9.8 m/s^2, so doubling the mass doubles the weight. The other ideas mix up different concepts: weight is not the distance an object falls, and not velocity times mass (that would be momentum). And weight is not the mass itself, since mass and weight respond differently to gravity.