What does mass measure in a body?

• A. The amount of space the body occupies
• B. The quantity of matter, determined by force applied for movement
• C. The density of the materials that constitute the body
• D. The energy contained in the body

Answer: (B)

Mass measures the quantity of matter in a body, which is fundamentally linked to the amount of substance contained within it. This attributes to not only how much "stuff" is present but also relates to the body's inertia—how it resists changes in motion when force is applied. When we talk about mass, we’re looking at how much matter is present that can be influenced by gravitational and other forces.

It's important to differentiate this concept from other options. The amount of space a body occupies relates to volume, not mass. Density refers to how compact the matter is within a given volume, which is a different property, and energy, while it can be a factor in the motion and state of a body, is not a measure of mass itself. Hence, understanding mass in the context of matter and force provides a clear distinction of its fundamental role in physical science.