Kinetic energy is the energy of an object in motion. It is defined as the work needed to accelerate an object from rest to a specific velocity. The formula for kinetic energy is KE = 1/2 mv², where m represents mass and v represents velocity. This form of energy is directly proportional to both the mass of the object and the square of its velocity, meaning that even a small increase in speed results in a large increase in kinetic energy. Understanding kinetic energy is crucial in fields such as physics, engineering, and mechanics.