Which expression defines Force?

• A. mass x acceleration
• B. distance/time
• C. velocity x acceleration
• D. Force x Velocity

Answer: (A)

Force is defined by F = m a, reflecting Newton’s second law: the net force on a body equals its mass times its acceleration. This captures why heavier objects resist changes in motion (inertia) and how acceleration scales with the applied push or pull. The units check out as newtons (kg·m/s^2). The other expressions don’t define force: distance over time is speed, not force; velocity times acceleration isn’t a standard quantity for force; and force times velocity relates to power only when considering how much work is done as the object moves in the direction of the force, not the force itself. So the mass-acceleration product is the correct definition.