When Do People Use Pulleys?

Pulleys are used for many things.

Essentially, a pulley is a wheel with a groove around its outside edge, in which a rope or cord fits. A pulley changes the direction of the force applied to an object or system, making it easier to lift or otherwise manipulate.

Washing Machines

In a washing machine, changing the size of the pulleys controlling the drum allows the motor to maintain a constant speed, and permits the drum to spin faster or slower. Large pulleys spin slower than small pulleys.

Dumb Waiters

In some older restaurants and homes, food and books were moved up and down between floors by a system of ropes and pulleys known as a dumb waiter. A dumb waiter is essentially a small elevator that eliminates the need for these items to be physically carried from floor to floor.

Other Applications

Other everyday uses of pulleys include water pumps and fan belts in automobiles, cranes at building sites and flag poles. In the home, pulleys are also used in Venetian blinds and in cassette tape and record players.

References

• Josie True: Pulley Activity
• Imagination Factory: Pulleys