Which of the following is NOT one of the six classical simple machines?

The six classical simple machines (Renaissance scientists, building on ancient Greek engineering): (1) LEVER — rigid bar pivoting on a fulcrum; (2) WHEEL AND AXLE — two cylinders of different radii fixed together; (3) PULLEY — wheel with a grooved rim for a rope or cable; (4) INCLINED PLANE — sloped surface; (5) WEDGE — two inclined planes back-to-back, used to split (axes, chisels) or hold (doorstops, nails); (6) SCREW — inclined plane wrapped around a cylinder. A battery is not a simple machine — it's an electrochemical device that stores and provides electrical energy. Simple machines change the direction or magnitude of mechanical force; they don't create energy, only transform mechanical advantage. All complex machines are combinations of simple machines: (1) BICYCLE — wheel and axle (wheels), levers (pedals, crank, handlebars), pulleys/chain (gear system), wedges (rim brakes); (2) SCISSORS — two first-class levers sharing a fulcrum; (3) CAN OPENER — lever (handles), wheel and axle (turning mechanism), wedge (cutting blade); (4) WHEELBARROW — second-class lever; (5) CAR JACK — screw and lever; (6) CRANE — pulleys, levers, wheels. The principles of work, energy, and mechanical advantage learned through simple machines apply to all mechanical systems. ASVAB MC questions on simple machines test identification, calculation of mechanical advantage, and application to real tools.