What is the main function of a pulley in mechanical systems?

The primary function of a pulley in mechanical systems is to change the direction of a force. When a force is applied to one side of a pulley, it allows that force to be redirected to lift or move a load on the opposite side. This is particularly useful in scenarios where lifting or pulling a load directly upwards might not be practical or effective. By using a pulley, the user can apply force downward or horizontally while still achieving the desired vertical movement of the load. The design of the pulley facilitates this redirection efficiently, making it an essential component in various applications, from construction to transportation.

In contrast, while storing energy and providing connections between components are important aspects of some mechanical systems, they do not represent the primary function of a pulley. Similarly, a pulley does not inherently reduce the weight of a load but rather assists in managing the force required to lift it, enhancing mechanical advantage instead.