On a level surface, which force always acts upward?

On a level surface, which force always acts upward?

• A. Weight
• B. Normal force
• C. Friction
• D. Air resistance

Answer: (B)

The upward force is the normal force, the contact force the surface exerts on the object to support it. It acts perpendicular to the surface and points away from the surface, so on a level surface it pushes upward. This force balances the downward weight when there’s no acceleration into or away from the surface, keeping the object from sinking or lifting off. Weight pulls downward due to gravity. Friction runs along the surface and opposes motion, not inherently upward. Air resistance depends on motion through air and acts opposite the direction of travel, not necessarily upward.

The upward force is the normal force, the contact force the surface exerts on the object to support it. It acts perpendicular to the surface and points away from the surface, so on a level surface it pushes upward. This force balances the downward weight when there’s no acceleration into or away from the surface, keeping the object from sinking or lifting off.

Weight pulls downward due to gravity. Friction runs along the surface and opposes motion, not inherently upward. Air resistance depends on motion through air and acts opposite the direction of travel, not necessarily upward.