Which of the following performs mechanical work by transforming rotational motion?

The wheel and axle is a device that converts rotational motion into mechanical work, making it an essential component in various machinery and tools. The structure consists of a large wheel attached to a smaller axle; when the wheel turns, it causes the axle to turn as well. This transformation of motion allows for the efficient movement of loads, as the wheel can reduce friction and amplify force, enabling heavy objects to be moved easily over distances.

In contrast, the other options do not primarily transform rotational motion. A pulley is designed to change the direction of force applied to lift or lower loads but does not inherently involve rotational motion in the same way. An inclined plane provides a gradual slope to raise objects with less force but is also not reliant on rotational motion for its function. Similarly, a wedge is used to separate or cut objects rather than being associated with rotational movement. Thus, the wheel and axle stands out as the choice that specifically performs mechanical work through the transformation of rotational motion.