Power is defined as the rate at which what physical quantity is done or transferred?

1. Power is defined as the rate at which work is done, P = W/t. 2. Because work is a transfer of energy, power is equally the rate at which energy is expended. 3. Force, distance, and mass are quantities that appear inside the definition of work itself, but none of them alone is what power measures the rate of. 4. Only work, divided by the time it takes, correctly defines power. _Source: OpenStax College Physics (CC BY 4.0), Ch 7 "Work, Energy, and Energy Resources", section 7.7 Power_