What is Mass?

What is Mass?

• A. The amount of energy in a system.
• B. The volume of the object.
• C. The amount matter a body contains.
• D. The weight produced by gravity.

Answer: (C)

Mass is the amount of matter a body contains. It’s an intrinsic property that reflects how much stuff is present and also relates to inertia—the resistance an object has to changes in its motion. This is the best description because mass is not energy, nor is it the volume the object occupies. Energy describes how much work can be done or how the system stores motion and position, while volume is how much space the object takes up. Mass stays the same regardless of location, but weight—the gravitational force on that mass—changes with gravity (weight equals mass times the local gravitational acceleration). For example, a kilogram of iron and a kilogram of feathers have the same mass even though they take up different volumes, and their weights would differ if you change the gravitational environment.

Mass is the amount of matter a body contains. It’s an intrinsic property that reflects how much stuff is present and also relates to inertia—the resistance an object has to changes in its motion.

This is the best description because mass is not energy, nor is it the volume the object occupies. Energy describes how much work can be done or how the system stores motion and position, while volume is how much space the object takes up. Mass stays the same regardless of location, but weight—the gravitational force on that mass—changes with gravity (weight equals mass times the local gravitational acceleration). For example, a kilogram of iron and a kilogram of feathers have the same mass even though they take up different volumes, and their weights would differ if you change the gravitational environment.