Pulley Systems
Pulleys can make a load easier to lift by changing the direction of the force or by sharing the load between several sections of rope.
A fixed pulley mainly changes the direction of your pull. A movable pulley reduces the force needed, and a block-and-tackle with several supporting rope sections reduces it even further.
The trade-off is distance: the less force you use, the farther you must pull the rope. In real pulleys, friction means the advantage is slightly less than the ideal value.
Lift the same weight with each arrangement. Which one needs the least effort?
Additional Information
A single fixed pulley doesn’t reduce the force needed at all — it just changes the direction you pull, which is still useful for lifting. Adding a movable pulley to the system is what actually multiplies your lifting force, at the cost of pulling more rope through.
Cranes, elevators, and even window blinds all rely on pulley systems to move heavy loads with manageable effort.
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