Which statement about weight is true?

Which statement about weight is true?

• A. Weight is a measure of the amount of matter.
• B. Weight is measured in kilograms.
• C. Weight is the mass of an object at rest.
• D. Weight is the force of gravity on an object and is measured in Newtons.

Answer: (D)

Weight is the force of gravity acting on a mass. That makes weight a force, not a measure of how much matter an object contains. The correct statement is that weight is the force of gravity on an object and is measured in Newtons. On Earth, weight equals mass times the acceleration due to gravity (W = m g), so a 1 kg mass weighs about 9.8 Newtons. Because gravity changes with location, weight can vary while mass stays the same. The amount of matter in an object is its mass, which is measured in kilograms; weight uses Newtons. Saying weight measures the amount of matter is mixing up these concepts, and saying weight is measured in kilograms uses the wrong unit. Weight being the mass of an object at rest confuses a force with a property that exists independently of gravity.

Weight is the force of gravity acting on a mass. That makes weight a force, not a measure of how much matter an object contains. The correct statement is that weight is the force of gravity on an object and is measured in Newtons. On Earth, weight equals mass times the acceleration due to gravity (W = m g), so a 1 kg mass weighs about 9.8 Newtons. Because gravity changes with location, weight can vary while mass stays the same. The amount of matter in an object is its mass, which is measured in kilograms; weight uses Newtons. Saying weight measures the amount of matter is mixing up these concepts, and saying weight is measured in kilograms uses the wrong unit. Weight being the mass of an object at rest confuses a force with a property that exists independently of gravity.