What is the definition of power?

• A. Power = Force × Velocity
• B. Power = Work × Time
• C. Power = (Force × Distance)/Time
• D. Power = Mass × Acceleration

Answer: (C)

Power is the rate at which work is done or energy is transferred. It tells you how quickly something is delivering energy. The fundamental relation is P = dW/dt, meaning power is the work done per unit time. If a constant force moves an object a distance in the direction of the force, the work done is W = F × d. The average power over that interval is then P = W/Δt = (F × d)/t. This aligns with the idea that power is energy transfer per unit time.

Instantaneous power can also be written as P = F · v, the dot product of force and velocity. When the force and motion are aligned, F · v simplifies to F × v, which matches the idea that power equals force times velocity in that special case. Since d = v × t for constant velocity, (F × d)/t is the same as F × v.

The other options don’t describe power correctly. Mass × acceleration gives force, not power. Work × time would yield energy × time, not power. And power is not general definition as force × distance; that would give energy, not a rate.