AS Daily A Level Physics question
A small steel ball is released from rest and falls through air. Ignoring buoyancy, which statement best describes the resultant force on the ball from the moment of release until it reaches terminal velocity?
Answer
The correct answer is B.
Correct: B — It decreases in magnitude, remaining downward, approaching zero. A is wrong because drag grows with speed, so the resultant becomes less than weight soon after release. B is correct because increasing drag opposes the motion and steadily reduces the downward resultant to zero at terminal speed. C is wrong because higher speed increases opposing drag, which reduces, not increases, the resultant force. D is wrong because starting from rest the drag builds from zero up to equal the weight at terminal speed, so the resultant does not become upward before terminal velocity.