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AS Daily A Level Physics question

2026-01-09 OCR A Forces & Motion (M3) — drag and terminal velocity 3.2.2(d)(i)

Which statement must be true when a skydiver with the parachute fully open has reached terminal velocity during descent?

  1. A The speed is still increasing but more slowly.
  2. B The upward air resistance equals the skydiver’s weight, so acceleration is zero. (correct)
  3. C Air resistance is zero because the speed is constant.
  4. D The skydiver’s weight has reduced to match the air resistance.

Answer

The correct answer is B.

Correct: B — The upward air resistance equals the skydiver’s weight, so acceleration is zero. A says the speed is still increasing, but at terminal velocity the speed is constant. B is the only correct statement because balanced forces mean zero resultant force and hence zero acceleration. C is wrong because drag is not zero at constant speed; it balances weight. D is wrong because weight does not decrease; it is balanced by air resistance at terminal velocity.