Is windmill a working model of kinetic energy?
Anything that moves is a model of kinetic energy, whether it moves in translation (a block sliding down a ramp) or in rotation, such as a windmill. Wind transfers some its kinetic energy to the windmill. When the wind stops, the windmill keeps turning not because of any potential energy, but according to Newton’s Law about objects in motion. The windmill stops only if energy is extracted from it by a torque opposite to the direction of rotation, either through friction or other means. A block sliding down a ramp is much easier to construct.
