Which device demonstrates mechanical energy?

• A. Heat from a heater
• B. A magnet
• C. Food
• D. Windmill

Answer: (D)

Mechanical energy is the energy of motion or the ability to do work due to movement or position. A windmill shows this clearly because the wind’s force makes the blades rotate, giving the moving parts kinetic energy. That rotation can be used to do work, such as turning a generator or pumping water, which is exactly what mechanical energy does. The other options involve different forms of energy: heat from a heater is thermal energy, a magnet involves magnetic energy, and food stores chemical energy for biological processes rather than macroscopic motion. So the windmill best exemplifies mechanical energy through its moving, work-capable parts.