First class - the fulcrum is between the resistance and the effort. Second class - the resistance is between the fulcrum and the effort. The distance from the effort to the fulcrum is called the effor...First class - the fulcrum is between the resistance and the effort. Second class - the resistance is between the fulcrum and the effort. The distance from the effort to the fulcrum is called the effort arm (rE); the distance from the fulcrum to the resistance is called the resistance arm (rR). Thus the mechanical advantage is then FR/FE, or the effort arm divided by the resistance arm:
