What force slows down moving objects by acting through the air?

• A. Air Resistance
• B. Mass
• C. Sliding friction
• D. Rolling friction

Answer: (A)

Air resistance is the drag force that acts on objects moving through air, opposite to their motion. It slows them down because as the object moves, it pushes air molecules aside and through, creating a backward push on the object. The faster you go or the larger your cross-sectional area, the greater this drag becomes, which is why things feel harder to push through air at high speeds and why skydivers reach a speed where drag balances gravity (terminal velocity).

Mass is not a force that slows things by itself—it’s a measure of inertia, the tendency of an object to keep moving unless another force acts. Friction in sliding or rolling forms occurs when surfaces contact each other, not through the air, so those forces don’t fit the clue about acting through the air.