AS Daily A Level Physics question
Two e-scooters A and B start from rest at the same place and move in the same straight line. For 0–10 s, their velocity–time graphs are straight-line segments: A increases uniformly from 0 to 6 m/s by t = 6 s, then stays at 6 m/s until t = 10 s. B increases uniformly from 0 to 4 m/s by t = 4 s, then continues increasing uniformly to 8 m/s by t = 10 s. Which statement must be true about the distances travelled by t = 10 s?
Answer
The correct answer is D.
Correct: D — Scooter B travels 2 m further than Scooter A. A is wrong because calculating areas gives A: 0.5×6×6 + 6×4 = 18 + 24 = 42 m, so A does not go further. B is wrong because the difference is not 4 m; B’s distance is 44 m, giving a 2 m advantage. C is wrong because starting together and moving for the same time does not guarantee equal distance when the v–t areas differ. D is correct since B: 0.5×4×4 + [(4+8)/2]×6 = 8 + 36 = 44 m, which is 2 m more than A’s 42 m.