A pulley is a simple machine that consists of a wheel with a groove around its circumference, typically used to lift heavy objects by pulling a rope or cable through the groove.
A pulley works by changing the direction of the force applied to an object. By using a rope or cable, the force applied downwards can be redirected upwards, making it easier to lift heavy objects.
A fixed pulley is attached to a stationary object, while a movable pulley is attached to the object being lifted. A fixed pulley only changes the direction of the force, while a movable pulley also provides a mechanical advantage by reducing the amount of force needed to lift the object.
The number of pulleys needed to lift an object depends on the weight of the object and the mechanical advantage desired. Generally, the more pulleys used, the easier it is to lift the object.
Yes, a pulley system can be used to move objects horizontally by attaching the pulleys to a fixed point and using a rope or cable to pull the object along the ground.