Science
What is Pulley?
A pulley is a simple machine made of a wheel with a groove that a rope or cable runs over. It lets you change the direction of a force — pulling down to lift something up — and, with multiple pulleys, lift heavy loads with much less effort.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains pulley.
Key things to understand
- 1A single fixed pulley changes the direction of your pull (down to up) but not the force needed.
- 2Adding more pulleys (a block and tackle) spreads the load across several rope sections, so you pull with less force.
- 3The trade-off is distance: to halve the force, you pull twice as much rope.
- 4Pulleys are used in cranes, lifts, flagpoles, sails, and gym equipment.
- 5More supporting rope sections means greater mechanical advantage.
Frequently asked questions
- How does a pulley make lifting easier?
- A single pulley lets you pull down (easier, using your weight) to lift a load up. Multiple pulleys share the load across several rope sections, so each pull needs less force.
- What's the difference between a fixed and a movable pulley?
- A fixed pulley stays in place and only changes the direction of force. A movable pulley moves with the load and reduces the force needed, at the cost of pulling more rope.
- Where are pulleys used?
- Cranes, elevators, flagpoles, window blinds, sailboats, and weight machines all use pulleys to lift or move loads more easily.