According to Teach Engineering, a pulley system helps to perform work by switching directions of force and simplifying the movement of large objects. Different types of pulley systems include fixed, movable and multiple.
In a fixed pulley system, the wheel is fixed to a shaft so users can take advantage of gravity, balance an object, and help raise objects above their head. However, a fixed pulley gives no mechanical advantage, as the input force that the user provides is equal to the force of the pulley.
Movable pulleys utilize a movable wheel and differ in other respects. According to Education.com, movable pulleys have a greater mechanical advantage, meaning that the input force is less than the force of the system. Both systems also require separate amounts of rope pulls. Experts say that movable pulleys require more rope pulls by the user as the weight is lighter, but fixed pulleys require less rope pulls.
In addition, the multiple pulley is comprised of both fixed and movable pulley systems. These pulleys are easiest to lift objects with, as the mechanical advantage increases in tandem with the inclusion of more ropes, as cited by Teach Engineering. Applications of pulley systems are seen in flagpoles, modern elevators and weightlifting machines.