The most obvious form of energy is kinetic energy, the energy of motion. It’s

easy to see when kinetic energy is transferred into or out of an object. As kinetic

energy leaves an object, the object slows down; thus moving water slows down as

it turns a gristmill, and a bowling ball slows down as it knocks over bowling

pins. Conversely, as kinetic energy enters an object, the object speeds up. A baseball

moves faster as you do work on it during a pitch; you’re transferring energy from

your body into the baseball, where the energy becomes kinetic energy in the baseball’s

motion.