Terminal velocity balances gravitational and drag forces

Steps:

• Terminal velocity occurs when a skydiver's speed is constant, meaning net force is zero.
• The downward force is the skydiver's weight due to gravity.
• The upward force is air resistance, which increases with speed until it matches weight.
• At balance, both forces act equally but oppositely.

Why A is correct:

• Newton's first law states that an object at constant velocity has zero net force, so weight (mg) equals air resistance (balanced forces).

Why the others are wrong:

• B ignores air resistance, which opposes and equals weight at terminal velocity.
• C ignores weight, the gravitational force always acting downward.
• D is incorrect because forces are present but cancel out, not absent.

Final answer: A