The energy an object has due to being in motion. The amount will depend on the mass of the object and how fast it is moving. Kinetic energy is also the work that’s needed to move an object with mass from rest to a particular speed. A roller coaster racing down a steep slope has kinetic energy. It has the energy needed to bring the cars from stationary to speedy. Because roller coaster cars are large, when they move very fast a lot of kinetic energy is involved.
In a sentence
In hybrid cars, computers control the wheels and convert the kinetic energy of the turning tires into electricity.