Diagram of a fixed pulley (brown) that can raise or lower a weight (dark gray) using a rope (light gray)

Movable pulley

A pulley is a simple machine that is used to lift heavy objects. Block and tackle system is a modified form of a pulley. Pulleys are usually used in sets designed to make the amount of force needed to lift something smaller.A pulley may be simple, but this is used in complex things like elevators! view more...