Which of the following equipment is typically powered by a PTO?

The correct choice is the post hole digger, as it is a piece of equipment that is commonly powered by a Power Take-Off (PTO) system found on tractors. The PTO is designed to transfer mechanical power from the tractor’s engine to implements attached to the rear or front of the tractor. A post hole digger utilizes this mechanical power to operate its auger, allowing it to efficiently drill holes in the ground for fence posts, signs, or other installations.

While air compressors can be run off of a tractor by other means, such as a belt system, they are not specifically equipped to operate through a PTO. A seed drill, on the other hand, typically relies on the tractor's power for mobility and seed distribution but does not necessarily use a PTO-driven system in the same way a post hole digger does; these machines usually operate independently of direct PTO connection. Similarly, a dump truck primarily relies on an engine and hydraulic systems for operation rather than a PTO setup, especially if it is not towed by a tractor.

In summary, the post hole digger is the prime example of equipment specifically designed to harness the power from a tractor’s PTO, making it the correct answer.