a simple machine consisting of a wheel (or similar lever) that turns an axle around which a cord is wound; its mechanical advantage is the ratio of the diameters of the wheel and axle
A simple machine consisting of an axle to which a wheel is fastened so that torque applied to the wheel winds a rope or chain onto the axle, yielding a mechanical advantage equal to the ratio of the diameter of the wheel to that of the axle
simple machine comprised of a wheel attached concentrically to a drum so that a rope will wind and unwind alternately from the wheel to the drum creating mechanical advantage