Which term describes the capacity to do work?

• A. Matter
• B. Volume
• C. Energy
• D. Density

Answer: (C)

Energy is the capacity to do work. Work is done when a force acts through a distance, and energy is the property that enables that action to occur. Different forms of energy reflect this potential: kinetic energy from motion, potential energy from position, chemical energy stored in fuels, electrical energy, and so on. For example, a stretched spring has potential energy that can do work when released, and a moving car has kinetic energy that can perform work as it pushes against its surroundings.

The other terms describe what something is made of or its amount, not its ability to do work: matter refers to the substance itself, volume is the space it occupies, and density is how much mass is packed into that space. Thus they don't capture the concept of doing work, whereas energy directly represents that capacity.