What is the Power Equation?

• A. Mass x Acceleration
• B. Distance x Time
• C. Velocity x Acceleration
• D. Force x Velocity

Answer: (D)

Power measures how fast work is done. The instantaneous power is the rate at which work changes as the body moves under the influence of a force. This is given by the dot product of force and velocity: P = F · v. When the force acts in the same direction as the motion, this simplifies to P = F × v, which is the idea behind the power equation. If the force opposes the motion, power is negative; if the force is perpendicular to the motion, it does no work and the power is zero.

So, the expression force times velocity is the correct way to represent the power the force delivers to a moving object. For example, pushing with 10 N while the object moves at 2 m/s yields 20 W of power.