A pulley is a simple machine that consists of a wheel on an axle or shaft designed to support movement and change the direction of force. It is commonly used to lift heavy objects by using a rope or cable that runs over the wheel. Pulleys can be found in various applications, from construction sites to elevators, making lifting tasks easier and more efficient. Pulleys can be classified into two main types: fixed and movable. A fixed pulley is attached to a structure and changes the direction of the force applied, while a movable pulley moves with the load, reducing the amount of force needed to lift it. By combining multiple pulleys, known as a pulley system, one can further reduce the effort required to lift heavy loads.