Under a constant net force, how does increasing mass affect acceleration?

• A. a = F/m; mass does not affect acceleration
• B. a = F/m; increasing mass increases acceleration
• C. a = F/m; increasing mass decreases acceleration
• D. a = F m; acceleration independent of force

Answer: (C)

Acceleration follows a = F/m. With a constant net force, changing mass changes acceleration inversely. If you push with the same force on a heavier object, it accelerates more slowly; on a lighter object, it speeds up more quickly. Doubling the mass halves the acceleration, quadrupling the mass quarters it, and so on. This happens because mass is the measure of inertia—the resistance to changes in motion—so a larger mass requires a smaller acceleration for the same push.