Kinetic energy is in motion or being used. The faster it is going, the more energy it has. Which statement best describes kinetic energy?

• A. Energy stored due to position
• B. Energy in motion; faster means more energy
• C. Energy due to chemical bonds
• D. Energy due to gravity only

Answer: (B)

Kinetic energy is the energy of motion. When something moves, it holds energy because work has been done to set it in motion, and how much energy it has depends on its speed (and its mass). The statement that best describes this is that kinetic energy is energy in motion, and faster means more energy. That’s because kinetic energy grows with speed; it’s proportional to the velocity squared (KE = 1/2 m v^2). So doubling the speed makes the energy quadruple, and increasing the mass at the same speed also increases the energy.

The other ideas describe different kinds of energy: energy stored due to position is potential energy, energy from chemical bonds is chemical energy, and energy due to gravity is a type of gravitational potential energy.