Which term describes the rate of doing work?

• A. The capacity to do work.
• B. The speed of an object in a direction.
• C. The amount of time.
• D. The rate of doing work.

Answer: (D)

Power is the rate at which work is done. The phrase describing “the rate of doing work” matches this idea exactly, since power measures how quickly energy is transferred or used over time (P = W/t). The other ideas are different concepts: capacity to do work refers to energy or potential to do work, not how fast it's done; the speed of an object describes motion (velocity); and the amount of time is just a duration, not a rate. So the option that uses the rate of doing work correctly points to power, the quantity that tells us how quickly work is performed.