Which term describes the energy of motion?

• A. Kinetic energy
• B. Thermal energy
• C. Photon energy
• D. Potential energy

Answer: (A)

Energy tied to motion is called kinetic energy. Any object in motion has this energy, and it increases with mass and with the square of its speed: KE = 1/2 m v^2. This means a heavier or faster object carries more energy as it moves. The other terms describe different kinds of energy: thermal energy is the collective microscopic motion and interactions within a substance, photon energy is the energy carried by light particles, and potential energy is energy due to an object's position in a field or relative height.