Which of the following best describes a pulley?

A pulley is best described as a device that can change the direction of force. This characteristic is fundamental to its operation; by using a rope or cable that runs through a grooved wheel, a pulley allows a user to lift a load by pulling downward on one end of the rope, which in turn raises the load upward.

This ability to redirect force makes pulleys especially useful in various mechanical applications, such as in construction, where heavy loads need to be lifted and moved efficiently. While other choices describe different types of simple machines—like levers, wheels and axles, and inclined planes—they do not capture the essential function of a pulley, which focuses specifically on altering the direction of applied force.