Terminal velocity is defined as

• A. The velocity at which gravity stops acting
• B. The velocity at which drag balances weight and net force becomes zero
• C. The maximum velocity the object can reach
• D. The velocity at which there is no air resistance

Answer: (B)

When an object moves through air, gravity pulls it downward while the air pushes upward as drag. Terminal velocity is the speed at which these forces balance, so the net force is zero and the object stops accelerating. At that moment the object continues moving at a constant speed because there’s no remaining force to speed it up or slow it down. This steady speed depends on factors like the object's mass, shape, size, and the air's density and viscosity, so heavier or more streamlined bodies reach a higher terminal velocity in the same air.

The other ideas aren’t correct because gravity doesn’t stop acting, so there’s still a downward force. It’s not simply the maximum speed the object can ever reach—terminal velocity is the steady speed under constant conditions, and changing conditions (like air density or orientation) changes the terminal velocity. Also, terminal velocity relies on some air resistance; if there were no air resistance, there wouldn’t be a balanced drag force to reach terminal velocity.